We searched the PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) electronic databases for the following terms: 1) “immune checkpoint inhibitors” or “PD-1” or “PD-L1” or “CTLA-4” and 2) “myocarditis” or “cardiotoxicity”. The gene discussed is CTLA4; the disease is myocarditis.