RecruitingPhase 2Drug trialSurgical Pembro +/- Olaparib w TMZ for rGBMThis research study is studying a combination therapy as a possible treatment for recurrent glioblastoma (GBM), a brain tumor that is growing or progressing despite earlier treatment. The names of the study interventions involved in this study are/is: * Pembrolizumab * Olaparib * Temozolomide (Temodar)