CTLA4 and glioblastoma: There is an incomplete understanding of the prevalence of the aforementioned markers’ prevalence of expression (for example, PD-1, PD-L1, CTLA-4, and ligands CD80 or CD86) in different GBM stages or subtypes (as defined by methylation class), be it newly diagnosed or recurrent/progressive, or after specific treatments (post-radiation vs. post-chemotherapy).