Berghoff et al., analyzing a cohort of 43 WHO grade II/III gliomas (39 IDH-mut, 4 IDH-wt) and 14 IDH-mut GBMs, demonstrated that IDH-mut tumors have fewer CD3+ and PD1+ tumor-infiltrating lymphocytes (TILs) and decreased expression of programmed cell death ligand (PD-L1) compared to their wt counterparts (series of 117 IDH-wt GBMs) [48]. Here, IDH1 is linked to central nervous system cancer.