Programmed cell death protein 1 (PD-1, encoded by PDCD1 gene) and one of its two known ligands, the programmed death ligand-1 (PD-L1, encoded by CD274 gene) are among the therapeutically most important checkpoint proteins that mediate tumor-induced immune suppression through T-cell downregulation [1]. The gene discussed is PDCD1; the disease is neoplasm.