CTLA4 and glioblastoma: While the efficacy of the anti-PD-1 agent nivolumab [20] and the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) agent ipilimumab [21] have been recently reported for glioblastoma, there is currently no evidence of these drugs’ superiority over bevacizumab for recurrent glioblastoma.