CTLA4 and metastatic melanoma: Immune checkpoint inhibitors, such as anti-cytotoxic T Lymphocyte associated protein- 4 (CTLA-4) antibody (Ipilimumab) and anti-PD-L1 antibodies (atezolizumab, druvalumab, and avelumab) have shown some clinical benefits in the treatment of patients with advanced-stage metastatic melanoma.