Immune checkpoint inhibitors, targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and the programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathways have shown remarkable potential in several types of cancer [38].The expression of CTLA-4 and CD161 (KLRB1) were lower in high-risk groups, which also indicated that patients with high-risk scores may be not suitable for ICIs treatment. This evidence concerns the gene PDCD1 and cancer.