Idiopathic inflammatory myopathies (IIMs) comprise a spectrum of autoinflammatory disease characterized primarily by muscle inflammation, with secondary involvement of diverse organs including joints, skin, lungs, heart, and the gastrointestinal system. Managing these conditions poses considerable challenges, often inflicting profound distress on the afflicted individuals. Encouragingly, the deployment of chimeric antigen receptor (CAR) T cell therapy has demonstrated promising efficacy across various autoimmune diseases, extending hope for ameliorating the burden of IIM. This review provides an overview of the role of B cells in IIM pathogenesis, currently available B cell-depleting therapies, reasons for their lack of efficacy, and the application of CD19 CAR T cell therapy in the management of IIM, encompassing indications, efficacy, and tolerability profiles in these patient populations. Through this comprehensive review, we propose clinical trial design, target population, response criteria, and long-term follow-up measures for future clinical trials focusing on CD19 CAR T cell therapy in IIM. This overview aims to streamline research efforts and enhance the efficacy of therapeutic interventions in challenging cases.