PDCD1 and melanoma: The superiority of PD-1 inhibition has recently been confirmed in several retrospective studies [53,54,55,56].The first prospective phase I trial of nivolumab, ipilimumab and extracranial radiotherapy (30 Gy in 10 fractions or 27 Gy in 3 fractions) in patients with advanced melanoma demonstrated that RT-nivolumab-ipilimumab combination appears safe compared with historical data of nivolumab and ipilimumab alone.