ENTPD1 and neoplasm: The intratumoral abundance of CD39+CD8+ TILs also correlated with earlier tumor stage and improved overall survival, and a CD39+CD8+ TIL-derived gene signature predicted ICI response and prognosis, supporting CD39 as a practical biomarker to enrich tumor-reactive CD8+ TILs and to improve adoptive cell transfer strategies in future clinical practice.