Immune checkpoint inhibitors (ICI) have revolutionized the field of oncology, by reshaping the prognosis of many cancers and are progressively becoming the standard of care. One of the costs of these advances is the emergence of a new spectrum of immune-related adverse events (irAEs), of which cardiovascular irAEs are particularly feared. ICI-induced myocarditis is often a diagnostic challenge because of the vast heterogeneity of clinical presentations, and it is associated with a high mortality rate of around 50%. The present article summarizes the cardiac manifestations, the diagnostic strategy and the therapeutic management of patients with ICI-induced myocarditis used in the treatment of cancer.