Chemotherapy and Tislelizumab With Split-course HFRT for Locally Advanced Rectal Cancer

7Gy/F, d7, q3w, 5 cycles

CAPOX chemotherapy will commence on day 1 for each of six cycles: oxaliplatin 130 mg/m\^2 intravenous infusion on day 1,followed by capecitabine 1000 mg/m\^2 administered orally twice daily on day 1 to 14 of a 21-day cycle.

Tislelizumab 200 mg intravenous infusion on day 1 of each 21-day cycle for each of six cycles.