The second patient was a man aged 55 years with a history of stage II, right-sided colon cancer...Pathology findings from a biopsy were significant for infiltrating colonic adenocarcinoma with loss of nuclear expression of PMS2....the patient was started on neoadjuvant immunotherapy with nivolumab at 3 mg/kg and ipilimumab at 1 mg/kg intravenously every 3 weeks. The patient tolerated treatment well...with grade 2 tumor regression and no obvious residual tumor.