The world of flow cytometry is rapidly evolving. Peripheral blood, bone marrow aspirate, and cerebrospinal fluid are all specimens that can be analyzed using flow cytometry. Flow cytometry is most commonly indicated for both benign and malignant hematologic processes. It can aid in several clinical areas, including diagnosis, treatment plans, and monitoring residual or relapsed disease. Flow cytometry has been used for many years in clinical practice. As flow cytometry has advanced, more complex questions and diseases have been diagnosed, explained, and monitored.