ICB using inhibitors (anti-PD-1, anti-CTLA-4, anti-lymphocyte activation gene (LAG)-3, anti-T-cell immunoglobulin and ITM domain (TIGIT), anti-T-cell immunoglobulin and mucin-domain containing (TIM)-3, etc.)have shown promising outcomes in preclinical studies in a mouse tumor model in many cancer types including GBM [19,108,109,110,111,112]. This evidence concerns the gene PDCD1 and cancer.