Keywords: ACR, acute cellular rejection; CNI, calcineurin inhibitor; CTLA-4, cytotoxic T-lymphocyte-associated antigen-4; EMB, endomyocardial biopsy; ICI, immune checkpoint inhibitor; ISHLT, International Society for Heart and Lung Transplantation; LVEF, left ventricular ejection fraction; NT-proBNP, N-terminal pro–B-type natriuretic peptide; PD-1, programmed cell death protein-1; PET, positron emission tomography; SOT, solid organ transplant; TTE, transthoracic echocardiogram; heart failure; immunotherapy; mTOR, mammalian target of rapamycin; myocarditis.