In order to establish a connection between programmed death-ligand 1 (PD-L1) expression and glioma grades as well as the presence of IDH1 mutations, it is necessary to investigate the expression of PD-L1 and isocitrate dehydrogenase-1 (IDH1) in glioma patients and assess their potential as predictive markers for glioblastoma multiforme (GBM) immunotherapy. Here, IDH1 is linked to central nervous system cancer.