CTLA4 and melanoma: Immune checkpoint inhibitors (ICIs) targeting programmed death-1 (PD-1), programmed death ligand-1 (PD-L1), and cytotoxic T lymphocyte antigen-4 (CTLA-4) have transformed the therapeutic landscape for multiple malignancies, including melanoma, non-small cell lung cancer (NSCLC), triple-negative breast cancer (TNBC), renal cell carcinoma, and Hodgkin lymphoma [1–4].