For example, CTLA-4 (Cytotoxic T-Lymphocyte Associated Protein 4) and PD-1/PD-L1 (Programed Death 1/Ligand-1)/inhibitors have greatly improved the poor prognosis of metastatic melanoma (Axelrod et al., 2018). The gene discussed is CTLA4; the disease is metastatic melanoma.