Researchers at Tokyo University of Science published a pan‑immunotherapy gene signature that predicts intratumoral CD8+ T‑cell clonal expansion, using multi‑site tumor mouse models and longitudinal single‑cell RNA and TCR sequencing. The Nature Communications study identified an “expansion signature” present in clones before proliferation and validated its predictive power across untreated and immunotherapy‑treated mice. An accompanying analysis and industry commentaries framed the finding as a potential biomarker to forecast which tumors will mount effective T‑cell expansions, informing patient selection and trial design for checkpoint inhibitors and cell therapies. BioCentury and other outlets linked the discovery to broader efforts to develop actionable immune biomarkers that correlate with durable responses and guide combination strategies.