CTLA4 and melanoma: Among them, immune checkpoint inhibitors targeting PD-1/programmed death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) has been widely tested and approved as treatment options for solid organ cancers such as non-small cell lung cancer, renal cell carcinoma, and melanoma (Wolchok et al. 2013; Motzer et al. 2015; Antonia et al. 2017).