PDCD1 and glioblastoma: Meanwhile, the combination of anti-CTLA-4 and anti-PD-1 antibodies relieved the immunosuppression of the GBM TME by promoting the secretion of cytokines like IL-1β, IL-2, IL-12, and TNF-α, which increased the proportion of M1 polarized TAMs and enhanced the immunosurveillance at the tumor site.