Long-term results from the Phase 2 NICHE-2 trial indicate that none of 111 patients with mismatch repair–deficient (dMMR) colon cancer treated with four weeks of neoadjuvant nivolumab plus ipilimumab experienced disease recurrence. All patients were alive at a median postoperative follow-up of 58.7 months. The study reinforces the durability potential of abbreviated immunotherapy in a biomarker-defined population. It also adds weight to ongoing discussions around de-escalation strategies in colorectal cancer. Because the dataset is from a single-trial setting, further work remains necessary to generalize across clinical populations and to define optimal patient selection for short-course regimens.