Mogamulizumab selectively binds to CCR4—which is highly expressed in malignant T cells—and induces antibody-dependent cellular toxicity, thus destroying tumor cells [20,30].Lacutamab (IPH4102) binds to CD158k, a cell surface marker aberrantly expressed in patients with SS [31]. IPH4102 is designed to deplete CD158k-expressing cells via antibody-dependent cell cytotoxicity and phagocytosis [22,32]. The gene discussed is CCR4; the disease is synovial sarcoma.