Multivariate logistic regression showed that CK‐MB (adjusted odds ratio [OR]: 1.775, 95% confidence interval [CI]: 1.055–2.984, p = 0.031) was the independent risk factor of the development of ICI‐associated myocarditis, and cTnI (adjusted OR: 1.021, 95% CI: 1.002–1.039, p = 0.03) and NLR (adjusted OR: 1.890, 95% CI: 1.026–3.483, p = 0.041) were the independent risk factors of ICI‐associated severe myocarditis. The gene discussed is TNNI3; the disease is myocarditis.