New studies connected gut microbiota to systemic T cell plasticity and tumor control, demonstrating that certain intestinal CD4+ T cells primed in the gut can traffic to tumors and adopt anti‑tumor phenotypes. The Nature study mapped microbial cues shaping T cell identity and showed functional consequences for tumor immune surveillance. A complementary report linked gut dysbiosis to immunoresistance mechanisms in cancer, detailing microbial and metabolic pathways that blunt therapy responses. Together, the papers identify actionable microbial signals and suggest microbiome modulation could enhance immunotherapy efficacy. Researchers and biotechs focused on microbiome therapeutics and biomarkers will likely prioritize translational studies to test whether targeted microbial interventions can reprogram T cell states and overcome therapy resistance.