In particular, immune checkpoint blockades have been developed using antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death-1 (PD-1), and programmed cell death ligand-1 (PD-L1), and PD-1 inhibitors have been approved for melanoma, non–small cell lung cancer, renal cancer, Hodgkin’s lymphoma, bladder cancer, and head and neck cancer (Table 1). This evidence concerns the gene CD274 and head and neck cancer.