PDCD1 and cancer: By monoclonal antibody-mediated blocking of certain IC-molecules, mainly the programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4), cancer cells immune evasion can be reprogrammed and an immune response against cancer cells can be induced (2).