Several U.S. Food and Drug Administration (FDA)–approved cancer immunotherapy strategies exist for melanoma treatment including checkpoint blockade [ipilimumab (anti–CTLA-4) and pembrolizumab (anti–PD-1)], oncolytic viral therapy (talimogene laherparepvec), and combinational checkpoint blockade [nivolumab (anti–PD-1) + ipilimumab] (3). Here, CTLA4 is linked to cancer.