Case Presentation: A 70-year-old man with a history of stage III melanoma, previously treated with surgical resection and pembrolizumab, presented with diplopia and ptosis. Laboratory results showed significantly elevated high-sensitivity troponins and creatine kinase-MB. Initial electrocardiogram revealed complete atrioventricular block without ST-segment changes, necessitating the placement of a transvenous pacemaker. Echocardiogram showed an ejection fraction [...]