Glioblastoma (GBM) is a universally fatal cancer for which the standard of care has remained largely unchanged for the last 20 years. Recent work has demonstrated that most therapeutic trials for GBM fail due to complex mechanisms of immunosuppression mediated by both the innate and adaptive immune systems. Various metabolic alterations in the tumor microenvironment help maintain this local and systemic immunosuppression, of which the axis of hypoxia-driven tryptophan degradation has garnered substantial attention over the last decade. This paper synthesizes a much-needed elucidation of the immunometabolic reshaping of glioma, myeloid, endothelial, and lymphoid cell lineages induced by hypoxia. The current paper critically evaluates the role of IDO1/TDO2-mediated breakdown of tryptophan and the consequent accumulation of kynurenine, a metabolite that triggers GCN2- and AHR-mediated CD8+ T-cell exhaustion and supports regulatory T-cell differentiation and expansion. Furthermore, we propose a synthesis of mechanistic evidence that establishes a role for the Trp-GCN2-ATF4-VEGFA axis in hypoxia-induced immunosuppression, supporting that pro-tumoral metabolic dysregulation is directly linked to angiogenesis. In GBM, hypoxia and tryptophan–kynurenine pathway dysregulation operate as an integrated metabolic circuit that drives widespread immunosuppression. These mechanisms can be captured by a metabolic signature shared across nearly every cell type in the GBM microenvironment. Drawing on recent spatial transcriptomic, metabolomic, and pharmacologic studies, we outline how this metabolic axis shapes disease biology and how it can be targeted to restore effective antitumor immunity.

Thymic malignancies are rare cancers arising from thymic epithelial cells and are characterized by a highly diverse clinical phenotype, substantial histologic and morphologic heterogeneity, and frequent associations with autoimmune syndromes. Although the clinical, immunological, and cytoarchitectural changes associated with thymomas have been increasingly elucidated in the contemporary literature, very few studies have interrogated the direct role of tumor staging and histological grading in shaping autoimmunity burden and infection risk. In this narrative review, we synthesize contemporary clinical, immunological, and morphologic evidence linking thymic architecture and selection defects to the spectrum of paraneoplastic autoimmunity (MG, pure red cell aplasia, Good’s syndrome) and to infectious vulnerability. We further appraise emerging therapeutic strategies, including immune checkpoint inhibition and adoptive cellular approaches, through a patient-stratified lens, emphasizing efficacy signals, immune-related adverse events, and practical considerations for selection and monitoring. We conclude by highlighting priorities for future investigation, including refining autoantibody signatures; mapping thymic microenvironments that drive tolerance failure, and prospectively evaluating stratified immunotherapeutic regimens that balance benefit with immune-mediated risk.