CD274 and glioblastoma: Currently, it is well recognized that PD-L1 present in tumor cells, dendritic cells, and macrophages within the TME has a key role in mediating T cell immunosuppression and predicting the therapeutic outcome of PD-L1/PD-1 blockade.26,27 While high PD-L1 expression has been strongly correlated with an unfavorable prognosis for GBM patients, its effectiveness as a predictive marker for patient response to ICPIs has been largely unsuccessful.