Cutaneous T-cell lymphomas (CTCL) are a group of heterogeneous tumors with different clinical manifestations, pathological changes, immunophenotypes and molecular biological characteristics, and their pathogenesis is not completely clear. In recent years, more and more evidence has indicated that the composition and function of tumor immune microenvironment contribute a lot to the development of CTCL. A deep understanding of the composition of the tumor microenvironment in CTCL can help to find more effective anti-tumor immunotherapies, and help clinicians predict the prognosis of the disease more accurately. This review summarizes basic and clinical research progress in CTCL immune microenvironment in recent years.