Considering that this patient had high-risk T4b stage of descending colon cancer with late clinical staging and dMMR status confirmed by immunohistochemistry, the Cadonilimab targeting both PD-1 and CTLA-4 was selected for neoadjuvant therapy, with the hope that the bispecific antibody would offer better therapeutic outcomes for T4 colon cancers. The gene discussed is CTLA4; the disease is colonic neoplasm.