The field of cancer immunotherapy has been forever changed by ICIs that block immunological checkpoints such cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed death 1 (PD-1) and its ligand (PD-L1), and PD-1 ligand 2 (PD-L2). This evidence concerns the gene PDCD1LG2 and cancer.