PDCD1 and neoplasm: Programmed cell death-ligand 1 (PD-L1) is a target of the class of checkpoint inhibitors, which block the interaction between programmed cell death-1 (PD1) on T cells and programmed cell death-ligand 1 (PD-L1) on tumor cells, thus preventing the inhibitory signal on T cells and restoring antitumoral T lymphocyte activity [19].