Many of the patients undergoing chemotherapy or radiotherapy for cancer are at increased risk of developing cardiovascular diseases. Recent evidence suggests that cardiac dysfunction and subsequent heart failure are mainly due to vascular toxicity rather than only to due to myocyte toxicity. However, not all of the vascular toxicity of cancer therapies can be explained by epicardial coronary artery disease. In fact, in the last decades, it has been found that myocardial ischemia may occur as a consequence of structural or functional dysfunction of the complex network of vessels, which cannot be seen by a coronary angiography: the coronary microcirculation. Nowadays many diagnostic and therapeutic options are available both in coronary microvascular dysfunction and cardio-oncology. Aim of this review is to suggest future theranostic implications of the relationship between cardiotoxicity in oncology and coronary microvascular dysfunction, showing common pathophysiologic mechanisms, proposing new diagnostic approaches and therapeutic options for cardioprotection.