Three chemokine antagonists have been approved: Maraviroc (a CCR5 antagonist) for anti-HIV treatment (Xu et al., 2014), Plerixafor (a CXCR4 antagonist) for the treatment of multiple myeloma or non-Hodgkin’s lymphoma (Uy et al., 2008), and Mogamulizumab (a CCR4 antagonist) for the treatment of mycosis fungoides or Sézary syndrome (Sato et al., 2018). This evidence concerns the gene CXCR4 and Sezary syndrome.