However, gliomas exhibit strong immunosuppressive properties: glioma cells upregulate immunosuppressive factors (e.g., PD-L1, IDO) to impair antigen presentation, while glioma-associated macrophages and regulatory T cells weaken immunity via inhibitory cytokine secretion and cytotoxic T lymphocyte depletion, respectively (10). The gene discussed is IDO1; the disease is central nervous system cancer.