Keywords: CITE-seq, cellular indexing of transcriptomes and epitopes by sequencing; CTLA-4, cytotoxic T-lymphocyte antigen 4; CyTOF, time-of-flight mass cytometry; ICI, immune checkpoint inhibitor; IRAE, immune-related adverse event; PD-1, programmed death-1; immunotherapy; mass cytometry; monoclonal antibody; myocarditis; scRNA-seq, single-cell RNA sequencing; scTCR-seq, single-cell T-cell receptor sequencing; treatment.