This is an open-label, multi-center, single-arm clinical study. All patients received 4-6 cycles total neoadjuvant therapy plus concurrent tislelizumab immunotherapy, then underwent clinical response assessment. Patients who achieved CR (cCR+ pCR confirmed by local resection of ncCR) continue tislelizumab combined with CAPOX for another 4 cycles and tislelizumab for 9 cycles, then Watch and Wait. Patients who did not achieved CR underwent total mesorectal excision (TME).