The immunotherapy with antibodies against immune checkpoint proteins cytotoxic T cell antigen 4 (CTLA-4) and programmed death receptor 1/ligand (PD-1/PD-L1) has greatly extended the lives of many melanoma patients, however, about 70% of patients show disease progression within 5 years (Atkins et al., 2021). The gene discussed is CTLA4; the disease is melanoma.