TPS488 Background: About 30.3-58.0% of patients who undergo esophagectomy may experience recurrence. The efficacy of postoperative chemoradiation has not been demonstrated in a randomized trial in patients with esophageal squamous cell carcinoma (ESCC) compared to surgery along. Therefore, it is urgent to explore more effective and safer postoperative regimen for resectable ESCC. Checkmate 577 has demonstrated immunotherapy can prolong disease free survival (DFS) for patients who have residual disease following preoperative chemoradiation and R0 resection. Anlotinib is an orally administered tyrosine kinase inhibitor that targets VEGFR1-3, FGFR1-4 and PDGFRα/β. In a randomized, double-blind phase 2 trial, the use of anlotinib in previously treated metastatic ESCC patients significantly improved progression-free survival (PFS) compared with placebo ( NCT02649361 ). TQB2450 is a novel humanized monoclonal antibody against PD-L1, which has shown encouraging activity in combination with anlotinib in the treatment of multiple tumors, such as biliary tract cancer (NCT03996408) and ovarian cancer (NCT04236362). The ALTER-E005 study is designed to evaluate the efficacy and safety of anlotinib combined with TQB2450as adjuvant therapy in ESCC patients. Methods: ALTER-E005 is a multi-center, single-arm, phase II study. A total of 30 patients will be enrolled. Eligible pts (≥18 years) must be histologically confirmed T1-2N1-3M0 or T3-4NanyM0 ESCC; received radical (R0) resection of ESCC with no recurrence in imaging examination within 6-12 weeks after surgery; ECOG PS 0–1. Patients enrolled will receive oral anlotinib 12 mg on days 1-14 and intravenous TQB2450 1,200 mg on day 1 every 3 weeks until disease recurrence. The primary endpoint is DFS. The secondary endpoints include safety, 1-year DFS rate, 3-year DFS rate, 1-year overall survival (OS) rate, and 3-year OS rate. Enrollment to the ALTER-E005 trial is currently ongoing in China. Clinical trial information: NCT05252078 .