Moreover, ubenimex is also an inhibitor of CD13, which can be used as an immune adjuvant to improve the immune status of the body.28 According to the meta-analysis of Hu et al.29 Ubenimex is widely used as an immunoregulator in the treatment of leukemia, non-small-cell lung cancer and bladder carcinoma to improve the effect of anti-tumor therapy. Here, ANPEP is linked to leukemia.