In recent years,the application of immunotherapy and advancements in flow cytometry detection technology have significantly broadened the clinical opplication of multi-parameter flow cytometry for deep phenotyping of immune cell subpopulations.The"Chinese Journal of Laboratory Medicine"has published a special report titled"Deep phenotyping and Clinical Applications of Immune Cell Subpopulations Based on Multi-parameter Flow Cytometry,"which synthesizes the current status and developments in the deep phenotyping of immune cell subpopulations through multi-parameter flow cytometry within clinical contexts,while also addressing the challenges encountered in laboratory testing to facilitate its standardized implementation in clinical diagnosis and treatment.