ICIs primarily work by inhibiting cytotoxic inhibitory signaling pathways that tumor cells exploit to evade immune detection, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1) on T cells, and programmed cell death ligand 1 (PD-L1) on tumor cells [3,4]. This evidence concerns the gene PDCD1 and neoplasm.