MGMT and glioblastoma: Two phase III clinical trials investigated nivolumab (a programmed death receptor-1 (PD-1) inhibitor) in combination with radiation therapy in patients with unmethylated MGMT GBM (CheckMate-498; NCT02617589), and in association with radiation therapy plus concomitant and adjuvant temozolomide in patients with methylated MGMT glioblastoma CheckMate-548; NCT02667587).