PDCD1 and melanoma: Initial retrospective series of patients with melanoma brain metastases treated with SRS or fractionated RT within 3–6 months of receiving anti-PD-1 therapy produced promising 1-year OS rates and significantly improved 6- and 12-month distant brain metastasis control and OS rates in those treated with SRS and anti-PD-1 therapy vs. SRS and chemotherapy (Table 2) [113, 114].