CTLA4 and neoplasm: Recent examples include antibody blockade of checkpoint receptors (e.g., cytotoxic T lymphocyte antigen 4 [CTLA-4], programmed death 1 [PD-1], or its ligand [PD-L1]), adoptive cell transfer (ACT), tumor-infiltrating lymphocytes (TILs), or T cells engineered to express tumor-reactive T cell receptors (TCRs) (1, 2).