BTLA and glioblastoma: In the case of mice depleted of CD4 + or CD8 + T-cells, there were no differences among the groups studied in terms of OS, suggesting that anti-PD-1 and anti-BTLA combination therapy provided a synergistic survival benefit in murine GBM, potentially through the reversal of immunosuppression of CD4+/CD8 + TILs [97].