Complete clinical response in a patient with locally advanced high-grade microsatellite instability/deficiency in mismatch repair rectal adenocarcinoma after short-course ipilimumab and nivolumab. (A): Endoscopic imaging, showing a bleeding rectal cancer 9 cm from the anal verge in a 33-year-old male patient with Lynch syndrome. (B): Magnetic resonance imaging (MRI) staging demonstrated a locally advanced rectal cancer (cT3 cN2 cM0). (C): Endoscopy and (D) MRI demonstrating a complete clinical response after short-course treatment with ipilimumab and nivolumab.