CTLA4 and colorectal carcinoma: For instance, it has been proved that immune checkpoint inhibitors (ICIs) that target programmed cell death 1 (PD‐1), cytotoxic T lymphocyte antigen 4 (CTLA4), or programmed cell death 1 ligand 1 (PDL1) benefit metastatic CRC patients with mismatch repair‐deficient and microsatellite instability high tumors.6