Immune checkpoint inhibitors (ICIs) have become a new standard of care in several cancers but often lead to undesirable immune-related adverse effects, including GI toxicity in up to 1/3 of patients. ICI-related colitis (irColitis) is generally treated with immunosuppressive medications such as steroids, but may be refractory in up to 50% of cases and require further treatments such as infliximab. The role of vedolizumab (VDZ), a newer gut-selective agent approved for inflammatory bowel disease (IBD), remains unclear.