The use of a novel IDO1 inhibitor, BGB-5777, showed survival benefits in a mouse GBM model when combined with ICI and RT [134], forming the basis for ongoing/future trials (combined with ICI and RT +/− other therapies), including BMS-986205 (NCT04047706) and epacadostat (NCT03532295). This evidence concerns the gene IDO1 and glioblastoma.