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 [10, 24]. This evidence concerns the gene PDCD1 and neoplasm.