Immune checkpoint blockade in oral squamous cell carcinoma: A systematic review of efficacy and emerging evidence

Objectives: Systematically review clinical efficacy, safety and biomarker utility of immune checkpoint blockade (ICB) in OSCC. Methods: PRISMA-guided search of PubMed, Scopus, Web of Science; trials and observational studies of anti-PD-1/PD-L1 and CTLA-4 included. Outcomes: OS, PFS, ORR, PD-L1, adverse events. Results: 15 studies included. Anti-PD-1 (nivolumab, pembrolizumab) show survival benefit and durable responses in recurrent/metastatic HNSCC subsets; combination therapy increases response but also toxicity. OSCC-specific data limited. Conclusion: ICB is promising for advanced OSCC in biomarker-selected patients; need for dedicated OSCC trials and validated predictive biomarkers.