In rectal cancer, recent studies suggested that anti–programmed cell death protein 1 (PD-1) monotherapy, when combined with different neoadjuvant treatment regimens, increased the complete response rate.25,26,27 However, the potential benefit of adding anti–cytotoxic T lymphocyte–associated protein 4 (CTLA-4) antibodies remains unclear. This evidence concerns the gene PDCD1 and rectal cancer.