The tumor microenvironment (TME) plays a crucial role in the progression of various cancers, particularly glioblastoma. Kloosterman et al. demonstrated that macrophages facilitate myelin recycling, which is essential for glioblastoma cells to meet their high metabolic demands. This study highlights the importance of lipid transfer from macrophages to cancer cells, suggesting potential metabolic vulnerabilities that could be targeted for therapeutic interventions (ref: Kloosterman doi.org/10.1016/j.cell.2024.07.030/). In another study, Jackson et al. explored the role of the cytokine Meteorin-like (METRNL) in T cell hypofunction within the TME, revealing that METRNL induces bioenergetic failure in CD8+ T cells, which could hinder the effectiveness of immunotherapies (ref: Jackson doi.org/10.1016/j.immuni.2024.07.003/). Additionally, Dobersalske et al. provided evidence of active lymphoid populations in cranial bone marrow adjacent to glioblastoma, challenging the notion of a uniformly immunosuppressed environment and suggesting that local immune responses may be more complex than previously thought (ref: Dobersalske doi.org/10.1038/s41591-024-03152-x/). Chen et al. further contributed to this theme by showing that ALOX5 promotes immunosuppressive M2 polarization in glioma-associated macrophages, indicating a significant role of lipid metabolism in immune modulation within the TME (ref: Chen doi.org/10.1136/jitc-2024-009492/). Overall, these studies underscore the intricate interplay between immune cells and tumor cells in the TME, revealing both challenges and opportunities for therapeutic strategies.