Immunotherapy in Recurrent/Metastatic Squamous Cell Carcinoma of the Head and Neck

First‑line programmed cell death 1 inhibitor plus chemotherapy vs. standard treatment in patients with recurrent or metastatic oral squamous cell carcinoma: A retrospective cohort study

Programmed cell death 1 (PD-1) inhibitor revives the killing effect of immune cells to prevent tumor progression. The present study aimed to evaluate the efficacy and safety of first-line PD-1 inhibitor + chemotherapy vs. standard treatment in recurrent or metastatic (R/M) oral squamous cell carcinoma (OSCC). A total of 51 patients with R/M OSCC were reviewed and divided into the PD-1 inhibitor + chemotherapy (n=21) and standard treatment (n=30) groups based on their actual treatments. The results of the present study demonstrated that the objective response rate (52.4 vs. 36.7%, P=0.265) and disease control rate (81.0 vs. 70.0%, P=0.377) were numerically elevated in the PD-1 inhibitor + chemotherapy group compared with those in the standard treatment group; however, the results did not reach statistical significance. The progression-free survival (PFS) was numerically increased (without statistical significance) in the PD-1 inhibitor + chemotherapy group compared with that of the standard treatment group (P=0.057). Specifically, the PD-1 inhibitor + chemotherapy group and the standard treatment group exhibited a median [95% confidence interval (CI)] PFS duration of 6.7 (1.6-11.8) and 5.2 (3.4-7.0) months, respectively. In addition, the PD-1 inhibitor + chemotherapy group demonstrated increased overall survival (OS) compared with that of the standard treatment group (P=0.032). Specifically, the PD-1 inhibitor + chemotherapy group and the standard treatment group exhibited a median (95% CI) OS duration of 18.3 (11.9-24.7) and 10.3 (7.9-12.7) months, respectively. Furthermore, multivariate Cox regression analysis indicated that PD-1 inhibitor + chemotherapy was independently associated with improved PFS [hazard ratio (HR)=0.308, P=0.002] and OS (HR=0.252, P=0.003). In addition, the incidence of grade 3-5 adverse events (AEs) was relatively low in both groups and the incidence of any grade of each AE was not significantly different between groups (all P>0.050). In conclusion, the first-line PD-1 inhibitor + chemotherapy group had improved efficacy and comparable safety compared with those of the standard treatment in patients with R/M OSCC.

IDO1 correlates with the immune landscape of head and neck squamous cell carcinoma: a study based on bioinformatics analyses

Background

Head and neck squamous cell carcinoma (HNSCCs) is a common cancer type with a high mortality rate and poor prognosis. Recent studies have focused on the role of immune checkpoints in HNSCC progression and in their potential use as prognostic markers and immunotherapeutic candidates. Some immune checkpoints, such as PD-1 and PD-L1, have been studied thoroughly in HNSCC. Other molecules, such as indoleamine 2,3-dioxygenase 1 (IDO1), have been investigated minimally.

Methods

IDO1 expression, prognostic potential, and association with the immune profile of HNSCC were explored using online databases, including GEPIA, UALCAN, TIMER2.0, cBioPortal, and LinkedOmics, which utilize TCGA datasets and are freely available for use. For validation purposes, seven pairs of primary and metastatic HNSCC were immunostained for IDO1.

Results

Our analysis revealed significantly higher expression of IDO1 in HNSCC, especially in HPV+ SCCs compared with healthy control tissue. However, IDO1 expression showed weak to no prognostic potential for overall and disease-free survival in HNSCC. IDO1 expression in HNSCC was positively correlated with several immune-related molecules, including most of the immune checkpoints. Additionally, GO enrichment analysis revealed that several immune-related pathways are positively correlated with IDO1 expression in HNSCC, such as response to type I interferon and lymphocyte-mediated immunity pathways. Finally, IDO1 expression positively correlated with infiltration of most of the immune cells in HNSCC, such as CD4+ T cells, CD8+ T cells, M1 and M2 macrophages, dendritic cells, and B cells.

Conclusion

IDO1 expression is closely correlated with the immune profile of the HNSCC. This observation should be explored further to elucidate the potential of targeting IDO1 as a novel immunotherapeutic approach for HNSCC.

Mechanisms of Resistance and Therapeutic Perspectives in Immunotherapy for Advanced Head and Neck Cancers

Immunotherapy is emerging as an effective treatment for advanced head and neck cancers and interest in this treatment modality has led to rapid expansion of this research. Pembrolizumab and nivolumab, monoclonal antibodies directed against the programmed cell death-1 (PD-1) receptor, are US Food and Drug Administration (FDA)- and European Medical Agency (EMA)-approved immunotherapies for head and neck squamous cell carcinoma (HNSCC). Resistance to immunotherapy is common, with about 60% of patients with recurrent or metastatic HNSCC not responding to immunotherapy and only 20-30% of patients without disease progression in the long term. Overcoming resistance to immunotherapy is therefore essential for augmenting the effectiveness of immunotherapy in HNSCC. This review details the innate and adaptive mechanisms by which head and neck cancers can become resistant to immunotherapeutic agents, biomarkers that can be used for immunotherapy patient selection, as well as other factors of the tumor microenvironment correlated with therapeutic response and prognosis. Numerous combinations and novel immunotherapies are currently being trialed, based on better understood immune evasion mechanisms. These potential treatments hold the promise of overcoming resistance to immunotherapy in head and neck cancers.

Identification of ZIC2 as a Potential Biomarker Linked with the Clinical Progression and Immune Infiltration of Oral Cancer: A Multicenter Study

Aim

To investigate the specific expression profile, clinicopathological significance and mechanism of Zic family member 2 (ZIC2) in oral cancer were unclear. Patients and Methods. We explored the expression pattern and clinicopathological significance of ZIC2 in oral cancer through performing in-house tissue microarray and integrated analysis global RNA-seq and microarrays containing large samples. The molecular basis of ZIC2 in oral cancer was further investigated in the aspects of transcription network and immune correlations. We also performed in vitro experiments and calculated drug sensitivity of oral cancer with different ZIC2 expression levels in response to hundreds of compounds.

Results

All data unanimously proved the significant overexpression of ZIC2 in oral cancer. The upregulation of ZIC2 was remarkably associated with the malignant clinical progression of oral cancer. ZIC2 was predicted to be targeted by miRNAs such as miR-3140, miR-4999, and miR-1322. The infiltration level of CD8+ T and central memory cells was positively related to the overexpression of ZIC2. Oral cancer patients with higher ZIC2 expression showed higher drug sensitivity to two compounds including AZD8186 and ERK_2240.

Conclusions

We demonstrated the upregulation of ZIC2 in oral cancer and its promoting effect on the clinical advancement of oral cancer. The potential clinical value of ZIC2 in oral cancer deserves attention.

The programmed death ligand 1 interactome demonstrates bidirectional signaling coordinating immune suppression and cancer progression in head and neck squamous cell carcinoma

BACKGROUND

The programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) are validated cancer targets; however, emerging mechanisms and impact of PD-L1 intracellular signaling on cancer behavior are poorly understood.

METHODS

We investigated the cancer cell intrinsic role of PD-L1 in multiple patient-derived models in vitro and in vivo. PD-L1 overexpression, knockdown, and PD-L1 intracellular domain (PD-L1-ICD) deletion (Δ260-290PD-L1) models were assessed for key cancer properties: clonogenicity, motility, invasion, and immune evasion. To determine how PD-L1 transduces signals intracellularly, we used the BioID2 platform to identify the PD-L1 intracellular interactome. Both human papillomavirus-positive and negative patient-derived xenografts were implanted in NOD-scid-gamma and humanized mouse models to investigate the effects of recombinant PD-1, anti-PD-L1, and anti-signal transducer and activator of transcription 3 (STAT3) in vivo.

RESULTS

PD-L1 intracellular signaling increased clonogenicity, motility, and invasiveness in multiple head and neck squamous cell carcinoma (HNSCC) models, and PD-1 binding enhanced these effects. Protein proximity labeling revealed the PD-L1 interactome, distinct for unbound and bound PD-1, which initiated cancer cell-intrinsic signaling. PD-L1 binding partners interleukin enhancer binding factors 2 and 3 (ILF2-ILF3) transduced their effect through STAT3. Δ260-290PD-L1 disrupted signaling and reversed pro-growth properties. In humanized HNSCC in vivo models bearing T-cells, PD-1 binding triggered PD-L1 signaling, and dual PD-L1 and STAT3 inhibition were required to achieve tumor control.

CONCLUSIONS

Upon PD-1 binding, the PD-L1 extracellular and intracellular domains exert a synchronized effect to promote immune evasion by inhibiting T-cell function while simultaneously enhancing cancer cell-invasive properties.

Comparative analysis of immune checkpoint inhibitors in first-line treatment of esophageal squamous cell carcinoma: a network meta-analysis

Aim: To evaluate the efficacy and safety of first-line immunochemotherapy in the treatment of advanced esophageal squamous cell carcinoma (CRD42021287033). Methods: PubMed, Embase, Cochrane Library and Web of Science were systematically searched to obtain randomized controlled trials, and the outcome indicators of the reports were compared and analyzed. Results: A total of 3163 patients from five reported randomized controlled trials were included in the meta-analysis. The results showed the comprehensive benefits of toripalimab combined with chemotherapy, in terms of overall survival (hazard ratio: 0.59; 95% CI: 0.43-0.81) and progression-free survival (hazard ratio: 0.58; 95% CI: 0.46-0.73). Conclusion: Toripalimab combined with chemotherapy may be a better choice for first-line immunochemotherapy, although this needs to be verified by clinical studies.

Squamous Cell Carcinoma of Duodenum Secondary to Metastasis From Recurrent Head and Neck Cancer: A Case Report and Literature Review

This report describes a case involving the diagnosis and treatment of squamous cell carcinoma (SCC) of the duodenum, which was found to be a metastatic lesion originating from recurrent head and neck cancer (HNC) in a 74-year-old female patient. The patient had a past medical history of gastroesophageal reflux disease (GERD), tonsillar SCC, and recurrent HNC. She presented with symptoms of burning, tingling, and numbness of the throat and left side of the tongue. Upon examination with an esophagogastroduodenoscopy, an ulcerated hard area mass was detected in the third portion of the duodenum. Biopsy results confirmed the mass to be a metastatic poorly differentiated SCC. The incidence of head and neck squamous cell carcinoma (HNSCC) metastasis to the duodenum is rare, likely due to the unique anatomic location and the lack of lymphatic drainage in the area. The patient was treated with a combination of paclitaxel, carboplatin, and pembrolizumab. This case underscores the significance of considering unusual sites of metastasis in HNSCC patients and utilizing advanced imaging modalities and immunotherapy to detect and treat these locations effectively.

Efficacy of first-line systemic treatment regimens for recurrent/metastatic head and neck squamous cell carcinoma: a network meta-analysis

PURPOSE

To evaluate the efficacy on overall survival (OS) and progression-free survival (PFS) of the first-line systemic therapy regimens on 6-, 12-, 18-, 24-, and 30 months in recurrent/metastatic head and neck squamous cell carcinoma (R/M-HNSCC) and figure out the best regimen.

METHODS

PubMed, Embase, The Cochrane Library, Scopus, and Google Scholars were systematically searched for studies in regard to the first-line systemic regimens for R/M-HNSCC from inception to March 2022. Odds ratios (ORs) were generated for dichotomous variants by network meta-analysis. The primary endpoint was OS, and the second endpoint was PFS. The software implemented was STATA 17.0 MP.

RESULTS

Eventually, 18 studies with 5298 patients and 12 first-line systematic regimens were enrolled. immunotherapy + chemotherapy (OR = 2.30, 95% CI 1.60-3.31) and single immunotherapy (OR = 1.91, 95% CI 1.33-2.76) were significantly superior to the EXTREME on OS at 30th month. Meantime, immunotherapy + chemotherapy (SUCRA = 87.7%) has the highest ranking. TPEx (OR = 1.61, 95% CI 1.05-2.48) showed significantly better efficacy compared with EXTREME on PFS at 12th month. Simultaneously, TPEx (SUCRA = 87.1%) had the highest ranking and was the long-lasting first-echelon regimen both in OS and PFS from a longitudinal perspective. It should be noted that EXTREME included platinum-based chemotherapy + fluorouracil + cetuximab, TPEx included docetaxel + cisplatin + cetuximab.

CONCLUSION

Considering the efficacy, safety, compliance, and economic profiles collectively, one of the standard first-line regimens, literally TPEx should be recommended as the best choice for R/M-HNSCC. Furthermore, more head-to-head trials are needed to confirm those findings.

Tertiary lymphoid structures in head and neck squamous cell carcinoma improve prognosis by recruiting CD8+ T cells

Tertiary lymphoid structures (TLSs) are formed in long-term chronic inflammation, promoting the local recruitment of lymphocytes, antigen presentation and regulation of immune response, correlated with a better prognosis for cancer patients. Although studies have been conducted to explore methods that accelerate the establishment of TLSs, related research in head and neck squamous cell carcinoma (HNSCC) is still lacking. In this study, we analysed data from The Cancer Genome Atlas and performed immunohistochemical staining analyses of 188 patient samples. The results showed that TLSs promoted the infiltration of immune cells. Patients with TLSs with high infiltration of CD8⁺ cells showed the best prognosis. Since lymphotoxin α (LTα) was significantly increased in tissues with TLSs, we overexpressed LTα in SCC7 cells (a mouse-derived HNSCC cell line) and established tongue-tumour-bearing models. The polychromatic observation of tissue sections showed that T-cell aggregation increased in the LTα cell group, and a grade 1 TLS was formed on the 12th day after inoculating the cells. Moreover, the tumour volume in the LTα group was significantly less than that of the control group, whereas both the number and the proportion of infiltrated CD8⁺ T cells were increased. The peripheral CD8⁺ cells in mice were removed, and no difference was observed in tumour size or TLS formation. Remarkably, we found that TLS led to an increase in the antitumour effect by recruiting CD8⁺ T cells in HNSCC, showing a CD8⁺ T-cell-dependent antitumour effect. Moreover, LTα overexpression in the tumour promoted the formation of TLSs.

The Ring Study: an international comparison of PD-L1 diagnostic assays and their interpretation in non-small cell lung cancer, head and neck squamous cell cancer and urothelial cancer

PD-L1 immunohistochemistry has been approved as a diagnostic assay for immunotherapy. However, an international comparison across multiple cancers is lacking. This study aimed to assess the performance of PD-L1 diagnostic assays in non-small cell lung cancer (NSCLC), head and neck squamous cell cancer (HNSCC) and urothelial cancer (UC). The excisional specimens of NSCLC, HNSCC and UC were assayed by Ventana SP263 and scored at three sites in each country, including Australia, Brazil, Korea, Mexico, Russia and Taiwan. All slides were rotated to two other sites for interobserver scoring. The same cohort of NSCLC was assessed with Dako 22C3 pharmDx PD-L1 for comparison. The PD-L1 immunopositivity was scored according to the approved PD-L1 scoring algorithms which were the percentage of PD-L1-expressing tumour cell (TC) and tumour proportion score (TPS) by Ventana SP263 and Dako 22C3 staining, respectively. In NSCLC, the comparison demonstrated the comparability of the SP263 and 22C3 assays (cut-off of 1%, κ=0.71; 25%, κ=0.75; 50%, κ=0.81). The interobserver comparisons showed moderate to almost perfect agreement for SP263 in TC staining at 25% cut-off (NSCLC, κ=0.72 to 0.86; HNSCC, κ=0.60 to 0.82; UC, κ=0.68 to 0.91) and at 50% cut-off for NSCLC (κ=0.64 to 0.90). Regarding the immune cell (IC) scoring in UC, there was a lower correlation (concordance correlation coefficient=0.10 to 0.68) and poor to substantial agreements at the 1%, 5%, 10% and 25% cut-offs (κ= -0.04 to 0.76). The interchangeability of SP263 and 22C3 in NSCLC might be acceptable, especially at the 50% cut-off. In HNSCC, the performance of SP263 is comparable across five countries. In UC, there was low concordance of IC staining, which may affect treatment decisions. Overall, the study showed the reliability and reproducibility of SP263 in NSCLC, HNSCC and UC.

Radiotherapy, Chemotherapy and Immunotherapy-Current Practice and Future Perspectives for Recurrent/Metastatic Oral Cavity Squamous Cell Carcinoma

Oral squamous cell carcinoma is the most common malignant epithelial neoplasm affecting the oral cavity. While surgical resection is the cornerstone of a multimodal curative approach, some tumors are deemed recurrent or metastatic (R/M) and often not suitable for curative surgery. This mainly occurs due to the extent of lesions or when surgery is expected to result in poor functional outcomes. Amongst the main non-surgical therapeutic options for oral squamous cell carcinoma are radiotherapy, chemotherapy, molecular targeted agents, and immunotherapy. Depending on the disease setting, these therapeutic approaches can be used isolated or in combination, with distinct efficacy and side effects. All these factors must be considered for treatment decisions within a multidisciplinary approach. The present article reviews the evidence regarding the treatment of patients with R/M oral squamous cell carcinoma. The main goal is to provide an overview of available treatment options and address future therapeutic perspectives.

Why responses to immune checkpoint inhibitors are heterogeneous in head and neck cancers: Contributions from tumor-intrinsic and host-intrinsic factors

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment including in head and neck squamous cell carcinomas (HNSCCs); however, only a fraction of HNSCC patients respond to ICI, whereas the majority fail to do so. The mechanisms underlying such variable responses remain incompletely understood. A better understanding of such mechanisms may broaden the spectrum of responding patients and enhance the rate of ICI response. HNSCCs exhibit a high level of genetic heterogeneity, manifested as mutations or amplifications of oncogenes (e.g., PIK3CA) and mutations of tumor suppressor genes (e.g., TP53). The immune tumor microenvironment (TME) of HNSCCs also varies significantly in composition and in relative abundance of distinct immune subsets such as CD8 tumor-infiltrating lymphocytes (TILs) or tumor-associated macrophages (TAMs), which represents a high degree of immunological heterogeneity. Here, we briefly discuss how heterogeneous ICI responses may be attributed to tumor-intrinsic factors, including genetic, transcriptional, and functional variations in tumor cells, and host-intrinsic factors, including cellular composition of the TME (e.g., CD8 TILs and TAMs), and host-intrinsic differences in the T cell receptor (TCR) repertoire of CD8 TILs. We also discuss the potential impact of these factors on designing strategies for personalized immunotherapy of HNSCCs.

Comparison of Second-Line Treatments for Patients with Platinum-Resistant Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma: A Systematic Review and Bayesian Network Meta-Analysis

Simple Summary

Which second-line treatment is the optimal choice for patients with platinum-resistant recurrent or metastatic head and neck squamous cell carcinoma remains unclear. To inform clinical decisions, we performed a network meta-analysis and systematic review to assess the relative efficacy and safety of second-line treatments for patients with platinum-resistant recurrent or metastatic head and neck squamous cell carcinoma. By synthesizing all available controlled trial evidence, PD-1 inhibitors significantly improved the overall survival, objective response rate, and treatment tolerance compared to the standard of care (docetaxel, methotrexate, or cetuximab). Afatinib presented a better progression-free survival and objective response rate than the standard of care. Compared with afatinib, PD-1 inhibitors had a better overall survival but a worse progress-free survival.

Abstract

Several new drugs and combination strategies can be used to treat patients with recurrent or metastatic head and neck squamous cell carcinoma in the second-line treatment. Questions regarding the relative efficacy and safety of any two of the multiple second-line treatment strategies have emerged. This study aims to compare second-line treatments for patients with platinum-resistant recurrent or metastatic head and neck squamous cell carcinoma. Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched to identify relevant articles. Direct and indirect evidence in terms of the objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events grade ≥ 3 (grade ≥ 3 trAE) were analyzed in this Bayesian network meta-analysis. A total of twenty-three trials involving 5039 patients were included. These studies compared 20 different treatments, including the standard of care (SOC: docetaxel, methotrexate, or cetuximab), PD-1 inhibitors (nivolumab or pembrolizumab), durvalumab, tremelimumab, durvalumab + tremelimumab, palbociclib + SOC, tivantinib + SOC, sorafenib + SOC, EMD1201081 + SOC, vandetanib + SOC, PX-866 + SOC, 5-fluorouracil + SOC, cixutumumab + SOC, gefitinib + SOC, cabazitaxel, nolatrexed, duligotuzumab, zalutumumab, gefitinib, and afatinib. Among the currently available treatment options, compared to the standard of care (SOC: docetaxel, methotrexate, or cetuximab), the PD inhibitor significantly improved OS, ORR, and grade ≥ 3 trAE. Afatinib presented a better PFS and ORR than the SOC. Compared with afatinib, the PD-1 inhibitor had a better OS but a worse PFS. In conclusion, compared to the SOC, the PD-1 inhibitor significantly improved the OS, ORR, and grade ≥ 3 trAE. Afatinib presented a better PFS and ORR than the SOC. Compared with afatinib, the PD-1 inhibitor had a better OS but a worse PFS.

TGF-β Signaling Pathway-Based Model to Predict the Subtype and Prognosis of Head and Neck Squamous Cell Carcinoma

Background: Although immunotherapy with immune checkpoint therapy has been used to treat head and neck squamous cell carcinoma (HNSCC), response rates and treatment sensitivity remain limited. Recent studies have indicated that transforming growth factor-β (TGF-β) may be an important target for novel cancer immunotherapies.

Materials and methods: We collected genomic profile data from The Cancer Genome Atlas and Gene Expression Omnibus. The least absolute shrinkage and selection operator method and Cox regression were used to establish a prognostic model. Gene set enrichment analysis was applied to explore biological functions. Tracking of indels by decomposition and subclass mapping algorithms were adopted to evaluate immunotherapy efficiency.

Result: We established a seven TGF-β pathway-associated gene signature with good prediction efficiency. The high-risk score subgroup mainly showed enrichment in tumor-associated signaling such as hypoxia and epithelial-mesenchymal transition (EMT) pathways; This subgroup was also associated with tumor progression. The low-risk score subgroup was more sensitive to immunotherapy and the high-risk score subgroup to cisplatin, erlotinib, paclitaxel, and crizotinib.

Conclusion: The TGF-β pathway signature gene model provides a novel perspective for evaluating effectiveness pre-immunotherapy and may guide further studies of precision immuno-oncology.

Differential responses to immune checkpoint inhibitor dictated by pre-existing differential immune profiles in squamous cell carcinomas caused by same initial oncogenic drivers

BACKGROUND

While immune checkpoint inhibitors (ICI) were approved for head and neck squamous cell carcinomas (HNSCCs), the response rate remains relatively low. Mechanisms underlying ICI unresponsiveness versus sensitivity are not fully understood.

METHOD

To better delineate differential responses to ICI treatment, we employed mouse SCC models, termed KPPA tumors that were caused by deleting p53 and hyperactivating PIK3CA, two most frequently mutated genes in human HNSCCs. We transplanted two KPPA tumor lines (TAb2 versus TCh3) into C57BL/6 recipients and examined the immune tumor microenvironment using flow cytometry. Furthermore, we employed single-cell RNA sequencing to identify the difference in tumor infiltrating lymphocytes (TILs).

RESULTS

We found that different KPPA tumors exhibited heterogeneous immune profiles pre-existing treatment that dictated their sensitivity or unresponsiveness to anti-PD-L1. Unresponsive TAb2 tumors were highly enriched with functional tumor-associated macrophages (TAMs), especially M2-TAMs. In contrast, sensitive TCh3 tumors contained more CD8 TILs with better effector functions. TAb2 tumor cells drastically expanded F4/80⁺ TAMs from bone marrow precursors, requiring CSF1 and VEGF. Consistently, a higher combined expression of VEGF-C and CSF1 predicts worse survival in PIK3CA^Amp/TP53^Mutated HNSCC patients. Unresponsive TAb2 tumors upregulated distinct signaling pathways that correlate with aggressive tumor phenotypes. While anti-PD-L1 did not affect the TME of TAb2 tumors, it significantly increased the number of CD8 TILs in TCh3 tumors.

CONCLUSIONS

We uncovered tumor-intrinsic differences that may underlie the differential responses to ICI by establishing and employing two SCC tumor lines, TAb2 vs. TCh3, both of which harbor TP53 deletion and PIK3CA hyperactivation. Our study indicates the limitation of stratifying cancers according to their genetic alterations and suggests that evaluating HNSCC tumor-intrinsic cues along with immune profiles in the TME may help better predict ICI responses. Our experimental models may provide a platform for pinpointing tumor-intrinsic differences underlying an immunosuppressive TME in HNSCCs and for testing combined immunotherapies targeting either tumor-specific or TAM-specific players to improve ICI efficacy.