PDCD1 and colorectal carcinoma: The NICHE-3 phase II trial assessed neoadjuvant nivolumab (anti-PD-1) with relatlimab (anti-LAG-3) in locally advanced dMMR CRC, achieving pathological responses (RVT ≤ 50%) in 97% of patients, including a 68% pCR rate, while maintaining acceptable safety.