CTLA4 and metastatic melanoma: The initial pivotal studies using the immune check-point inhibitors (ICIs) anti-Cytotoxic T Lymphocyte-Associated protein-4 (CTLA-4) and anti-Programmed Death/Ligand-1 (PD-1/PD-L1) led to durable remissions in a minority of patients with incurable metastatic cancers, such as metastatic malignant melanoma and non-small cell lung cancer (NSCLC) [15,16,17,18].