CTLA4 and heart failure: Of the 39 patients receiving two ICIs sequentially (PD-1/PD-L1 inhibitor + CTLA-4 inhibitor), five patients (12.8, 95% CI, 2.3–23.3) developed cardiomyopathy, and two patients (5.1, 95% CI, 0.0–12.1) developed heart failure.