Reassuringly, we found that most patients with advanced MSI-H colorectal cancer who experienced initial clinical benefit on immunotherapy overall did well after cessation regardless of a variety of disease and patient factors, including clinical features that are generally considered prognostically unfavorable, such as mutations in KRAS/NRAS (20) and BRAFV600E (21–23) and metastases to the peritoneum (24, 25). Here, KRAS is linked to colorectal cancer.