Unfortunately in 2019, two-phase III first-line trials recruiting patients with either methylated or unmethylated O6-methylguanine methyltransferase (MGMT) GBM using Nivolumab (a PD-1 inhibitor) concurrently with standard of care radiotherapy or chemoradiotherapy, failed to meet its primary end-point of improved progression-free or overall survival. Here, MGMT is linked to glioblastoma.