Among ICIs, the human anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) monoclonal antibody (mAb) ipilimumab was the first approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in 2011 15,16 for the treatment of late-stage melanoma, followed, few months later, by the BRAFi vemurafenib 17,18. Here, CTLA4 is linked to melanoma.