S100A9 and myocarditis: The data showed that the markers of infiltrated neutrophil (Lyz2, Csf1r Csf3r, S100a8, and S100a9), cardiac fibrosis (Col1a1), inflammation (Ly6c2 and IL‐1β), chemokine (Cxcl1, Cxcl9, Cxcl10, Ccl5, and Ccl8) and myocarditis (Timp1, AW112010, and Ctss) were significantly increased by anti‐CTLA‐4 m2a antibody (Figure 7e; highlighted by the dashed red circle and Figure S9, Supporting Information).