CD274 and head and neck squamous cell carcinoma: Programmed death protein-1 (PD-1)/programmed death receptor ligand (PD-L1) and immune checkpoint inhibitors (ICIs) have been approved by the Food and Drug Administration (FDA) for the treatment of non-small cell lung cancer, melanoma, and head and neck squamous cell carcinoma (3), etc. In recent years, PD-1/PD-L1 ICIs have achieved encouraging results in the treatment of advanced COAD (4–6).