CD274 and head and neck squamous cell carcinoma: For first-line treatment regarding OS (Figures 9A, C), R/M HNSCC patients with PD-L1 expression ≥1% showed significant OS benefits with pembrolizumab plus chemotherapy (HR=0.65, 95% CI: 0.53-0.80) and pembrolizumab (HR=0.78, 95% CI: 0.64-0.96) compared to SOC.