PDCD1 and metastatic malignant neoplasm: Immunotherapies, notably immune checkpoints inhibitors that target programmed death 1/programmed death ligand 1(PD‐1/PD‐L1) and cytotoxic T lymphocyte‐associated antigen 4 (CTLA‐4), had profoundly changed the way advanced and metastatic cancers are treated and dramatically improved overall and progression‐free survival.