Diabetes is a significant risk factor for heart failure (HF) and a common debilitating comorbidity. New research is leading to a better understanding of these comorbid conditions and improved care and outcome for patients. JACC: Heart Failure has published a special issue dedicated to the topic of HF and diabetes. The issue includes studies on outcomes following transcatheter mitral valve repair; a link between diabetes duration and risk for HF; new insights on phenotyping; mechanisms driving the benefits of sodium-glucose cotransporter-2 receptor inhibition; a look at different pathophysiological mechanisms in diabetes subtypes and HF subtypes; and exciting new results that show promise for treating HF with preserved ejection fraction as well as HF with reduced ejection fraction. Read the issue on JACC.org.