PDCD1 and glioblastoma: Some of the clinical trials that did not show significant survival benefit include nivolumab (anti-PD-1) and ipilimubab (anti-CTLA-4) in recurrent GBM (174); nivolumab vs. TMZ and radiation therapy in newly-diagnosed GBM (175); and nivolumab in combination with TMZ and radiation therapy in newly-diagnosed GBM (176).