Efficacy and Safety of Envafolimab Combined With Capecitabine and Lenvatinib as Postoperative Adjuvant Therapy in Resected Biliary Tract Cancer With High‐Risk Recurrence Factors: A Phase II Single‐Center Prospective Study. - Tian, Yitong; Lei, Tian; Ruan, Qingyang; Zhou, Xueying; Shen, Ruijing; Xie, Tianao; Li, Shijie; Cai, Xiujun; Chen, Mingyu (Cancer Medicine, 2026)