A phase Ib trial is currently evaluating neoadjuvant sintilimab (anti-PD-1) combined with hypofractionated radiotherapy (25 Gy/5 fractions) in locally advanced MSI-H/dMMR rectal cancer, reporting a 60% pCR rate and manageable toxicity, suggesting considerable potential in this subgroup [131]. This evidence concerns the gene PDCD1 and rectal cancer.