CTLA4 and melanoma: Despite the efficacy of immunotherapeutic strategies in multiple solid tumors, including melanoma, kidney, bladder, and lung cancer, the results of early trials investigating the blockade of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death-ligand 1 (PD-L1) in patients with advanced-stage PDAC have not demonstrated clinical benefits [3,4,5].