PDCD1 and cancer: By targeting various immune checkpoint molecules, such as programmed cell death protein 1 (PD‐1), programmed cell death 1 ligand 1 (PD‐L1), and cytotoxic T‐lymphocyte‐associated protein 4 (CTLA4) with monoclonal antibodies, T‐cells are enabled to develop specific capabilities to overcome cancer immune evasion and thus eventually target cancer cells.2