CTLA4 and melanoma: A CTLA-4 blocking antibody (ipilimumab) has been approved by FDA in 2011 for the treatment of metastatic melanoma, followed in 2014 by the approval of two PD-1 blocking antibodies, Pembrolizumab and Nivolumab, for treatment of advanced melanoma, squamous non-small cell lung cancer, and renal cell carcinoma43,44.