Infliximab for Treatment of Immune Checkpoint Inhibitor Colitis

The goal of this clinical trial is to compare the safety and effectiveness of infliximab compared to steroids for the treatment of immune checkpoint inhibitor-induced colitis (ICI colitis) in patients with stage III/IV skin cancer. The main questions this study aims to answer are: * How many patients treated with infliximab experience steroid-free disease resolution after 7 weeks? * How many patients treated with steroids experience steroid-free disease resolution after 7 weeks?

Inclusion Criteria: * Age ≥ 18 * Stage III/IV skin cancer * Treatment with CTLA-4 inhibitor alone or in combination with PD-1or PD-L1 blockade within the past 8 weeks * Clinically significant diarrhea resulting in the decision to pause immunotherapy treatment * Endoscopically visible colitis (Mayo 1-3) at the time of screening Exclusion Criteria: * Prior history of inflammatory colitis related to immune checkpoint inhibitors requiring treatment with \> 10 mg/day of prednisone or equivalent, or any other immunosuppressive medication * Concurrent immune-related Adverse Event (irAE) requiring treatment with systemic corticosteroids (dose equivalent of prednisone 10 mg/day or higher) or another systemic immune suppressing medication within the past 10 days * Current use of any immune suppressing biologic medication, or use within the last 4 weeks; immune stimulating medications such as checkpoint blockade are explicitly permitted * Current use of combination treatment with an investigation immunotherapy targeting a pathway other than PD-1 or PD-L1, concurrent chemotherapy, or targeted therapy * Previous adverse reaction to infliximab or corticosteroids * Colonic perforation or abscess present at the time of screening * History of Hepatitis B or C with a positive viral load, untreated mycobacterium tuberculosis, or active herpes zoster infection * Current bacterial infection requiring antibiotic treatment, or systemic fungal infection * Prior history of inflammatory bowel disease, microscopic colitis or segmental colitis associated with diverticulosis * Received more than 3 doses of systemic corticosteroids, or receive dsystemic corticosteroids at a dose exceeding 2mg/kg methylprednisolone or equivalent, within 72 hours prior to endoscopy