Introduction Immune checkpoint inhibitors can cause immune-related toxicity in various systems, with myocarditis being the most severe and life-threatening manifestation. This report presents a case in which myocarditis developed following administration of programmed cell death protein-1 (PD-1) inhibitors therapy. We describe the diagnosis and treatment of this patient in detail. Case report We present the case of a 59-year-old female diagnosed with post-operative esophageal cancer and hepatic metastases. The patient underwent second-line treatment with domestically-made PD-1 inhibitor, camrelizumab, in combination with paclitaxel (albumin-bound) and carboplatin for two cycles. During the course of treatment, an electrocardiogram (ECG) revealed ST segment elevation in leads II, III, aVF, V2, V3, and V4, along with T wave changes in leads I and aVL. Laboratory examinations showed abnormal levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT). Despite the absence of clinical symptoms, the patient was routinely hospitalized three weeks later. Based on the findings from the ECG, cardiac biomarkers, echocardiography, echocardiogram, cardiac magnetic resonance, and angiography, she was diagnosed with immune-checkpoint-inhibitors-related myocarditis. Management and outcome The patient received immunoglobulin (0.5 g/kg/day) and was initially given methylprednisolone (1000 mg/day). Methylprednisolone was gradually reduced to 40 mg/day in 2 weeks. During this time, the levels of biomarkers indicative of myocardial injury also exhibited a simultaneous decline. Discussion This case highlights the importance of early detection and prompt intervention, including initiating appropriate steroid therapy and discontinuing of immune checkpoint inhibitors. Such measures can effectively prevent morbidity and mortality, ultimately leading to an improved prognosis.