While clinical trials studying PD-1 and PD-L1 blockade are currently recruiting patients for GBM (NCT02337491, NCT02336165), the effectiveness of this approach has been characterized in treating refractory melanoma, providing an objective response rate (ORR) of approximately 15–30% as monotherapy with complete responses restricted to <6 % of patients.52,53. This evidence concerns the gene CD274 and melanoma.