Immune checkpoint inhibitor (ICI) therapy, including agents targeting programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), etc., has demonstrated notable clinical efficacy across multiple cancer types [1,2,3,4] and represents a revolutionary advancement in cancer treatment. This evidence concerns the gene PDCD1 and cancer.