CD8A and myocarditis: Depletion of CD8+ T cells significantly enhances survival in Pdcd1-/-Ctla4+/- mice, while adoptive transfer of immune cells from ICI-M donor mice into recipients (without CD8+ T cell depletion) induces fatal myocarditis, underscoring the indispensable role of CD8+ T cells in disease development (13) (Figure 1).