PDCD1 and neoplasm: Thus far, antibodies to inhibitory receptors cytotoxic T‐lymphocyte associated protein 4 (CTLA‐4) and the programmed death 1 (PD‐1)/programmed death ligand 1 (PD‐L1) axis have demonstrated clinical responses, including complete regression of lesions, and are approved for a dozen of tumor types.1, 2, 3