This phase II study evaluates whether early treatment with mycophenolate mofetil (MMF) plus prednisone improves liver inflammation caused by immune checkpoint inhibitors. The study includes patients who develop moderate to severe immune-related hepatitis after receiving PD-(L)1 or CTLA-4-based cancer therapy. The main goal is to determine how many patients experience improvement in liver function within 30 days while successfully tapering steroids. Safety and treatment-related side effects will also be monitored.