Checkmate 548 is a randomized phase 2 single blind study of TMZ with RT combined with nivolumab or placebo in newly diagnosed GBM with MGMT promoter methylation (NCT02667587); whereas Checkmate 498 is a phase 3 randomized study of nivolumab vs TMZ each in combination with RT for newly diagnosed GBM with an unmethylated MGMT promoter (NCT02617589). The gene discussed is MGMT; the disease is glioblastoma.