We classified outcomes of IDH‐wildtype GBM outcomes into three groups, as follows—good prognosis: for patients with methylated MGMT status, intermediate prognosis: for patients with unmethylated MGMT status and without CDKN2A homozygous deletion, and poor prognosis: for patients with unmethylated MGMT status and CDKN2A homozygous deletion. This evidence concerns the gene CDKN2A and glioblastoma.