PDCD1 and glioblastoma: Consistently, the population of interferon (IFN)-γ+/TNF-α+ CD8+ T cells was significantly increased in APOA1-expressing GBM tumors (Fig. 4l), while the population of PD-1+lymphocyte activating 3+ (LAG-3)+ CD8+ T cells was significantly decreased (Fig. 4m).