CTLA4 and glioblastoma: Early trials combining ipilimumab, GM-CSF, and bevacizumab in recurrent GBM reported partial responses in 31% of patients.372 Ongoing studies are evaluating ipilimumab in combination with TMZ, bevacizumab, and other ICIs.373 Additionally, IDO inhibition, which targets metabolic immunosuppression, has shown synergy with anti-PD-L1 and anti-CTLA-4 therapies in preclinical GBM models, resulting in 100% long-term survival.374 Furthermore, the current immunotherapeutic drugs in clinical trials are presented in Table 1.