Immune Checkpoint Inhibitor (ICI) therapy has become the standard of care for advanced cutaneous squamous cell carcinoma (CSCC). Data on the efficacy of ICI therapy in the treatment of Marjolin Ulcer is limited. Here, published in the Journal of Immunotherapy, we present a case series of 5 subjects treated with Marjolin Ulcer CSCC at the Massachusetts General Hospital. One patient had durable disease control for 1 year while on immunotherapy. Of the 4 patients that progressed while on ICI therapy, 2 patients achieved disease control at 5 months. 60% overall survival was observed in this limited cohort at 12 months after initiating ICI therapy.