PDCD1 and neoplasm: With the advent of immunotherapies, the tumor’s management has shifted from cytokine-based treatment to immune checkpoint inhibition, primarily of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) [8] and programmed cell-death protein 1 (PD-1) or its ligands (PD-L1 and PD-L2) [9].