Immune checkpoint inhibitors (ICIs) are essentially humanized monoclonal antibodies that target programmed cell death protein 1 (PD‐1), programmed cell death ligand 1 (PD‐L1), or cytotoxic T lymphocyte‐associated antigen 4 (CTLA‐4) (CD152) to activate T cells and promote the immune system to recognize and attack cancer cells.5 Here, CTLA4 is linked to cancer.