PDCD1 and glioblastoma: A previous meta-analysis stated that PD-1/PD-L1 inhibitors are better tolerated than predictable chemical and radioactive therapies, and such evidence in the literature regarding immunotherapeutic treatment with immune-checkpoint inhibitors in patients with GBM is taking place and are reporting use of monotherapy or a combination of PD/PDL-1 inhibitors with other drugs [37].