Neoadjuvant Chemoradiotherapy Plus PD-1 Blockade ± CTLA-4 Blockade for High-Risk Locally Advanced Rectal Cancer (pMMR/MSS): A National Multicenter, Prospective, Randomized Controlled Trial

The goal of this clinical trial is to learn whether adding ipilimumab N01 to standard pre-surgery treatment with radiation, chemotherapy, and sintilimab can improve outcomes for people with high-risk, locally advanced rectal cancer whose tumors are mismatch repair-proficient and microsatellite stable (pMMR/MSS). The study will also evaluate the safety of these treatments and whether some participants may be able to avoid major rectal surgery after a strong response.