Commonly used ICI include blockade of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) pathways, alone or in combination, to rejuvenate exhausted immune cells, including cytotoxic (CD8+) T cells, to promote tumor cell killing [1, 2]. This evidence concerns the gene PDCD1 and neoplasm.