CTLA4 and colorectal carcinoma: Concerning the immunotherapy of CRC, there is a considerable advantage demonstrated by the immune checkpoint blockade (ICB) that targets immune checkpoints such as programmed cell death 1 (PD1), programmed cell death 1 ligand 1 (PDL1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) [4].