However, the distinctively immune-privileged microenvironment that is formed due to the intrinsic expression of immunosuppressive cytokines, such as PD-1, PD-L1, TGF-β and IL10, and the lack of antigen-presenting cells (APCs) in the CNS result in challenges for glioma patient prognosis. Here, TGFB1 is linked to glioma.