PDCD1 and glioblastoma: Triple ICI therapy was selected based on an unprecedented survival in the phase 1 trial in advanced melanoma15, as well as the significantly superior activity of the combination of multiple ICIs versus ICI monotherapy in melanoma with a poor TME16,17 (low CD8+ T cells, low TMB and low interferon-γ (IFNγ)), metastases to the brain18 or primary resistance to anti-PD-1 therapy19—all features found in GBM.