Previous studies have shown that the inhibition of PD-L1 (CD274) signaling to treat cancer leads to subsequent myocarditis in humans, which can be alleviated with immunosuppression (Johnson et al, 2016; Mahmood et al, 2018; Moslehi et al, 2018; Salem et al, 2018; Esfahani et al, 2019). Here, CD274 is linked to myocarditis.