PDCD1 and metastatic melanoma: In December 2014, the FDA accelerated the approval of nivolumab, (brand name: Opdivo, also known as BMS-936558 and MDX1106) a humanized IgG4 anti-PD-1 monoclonal antibody that has a high affinity for PD-1, blocking the binding of PD-1 to its ligand PD-L1 (Fig. 2), for treating metastatic melanoma [38].