Subgroup analysis suggested greater pCR benefit with short course radiotherapy.<h4>Conclusion</h4>Among patients with pMMR non-metastatic rectal cancer, adding PD-1 inhibitors to standard nCRT improves pCR-most markedly when combined with short-course radiotherapy-with no statistically significant increase detected in high-grade neoadjuvant toxicity or major surgical morbidity. Here, RPL17 is linked to rectal cancer.