Monoclonal antibodies targeting immune checkpoints such as programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) have demonstrated remarkable efficacy, including in patients with colorectal cancer (CRC) [2,3]. Here, CTLA4 is linked to colorectal cancer.