CTLA4 and cancer: Cancer immunotherapy has emerged as a promising strategy for the treatment of various cancers by stimulating the immune system of the patient.207 Programmed death receptor 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA4) blocking antibodies, which are drugs approved by the Food and Drug Administration (FDA), have shown promising results in clinical trials for the treatment of various cancers.