CD274 and glioblastoma: In addition to adenoviruses, the antitumor effects of the poliovirus PVSRIPO combined with or without the anti-PD-1 agent pembrolizumab (NCT04479241) or the anti-PD-L1 agent atezolizumab (NCT03973879) in GBM patients are currently being evaluated in two ongoing phase I/II trials.