In PCa, STAT3 activation correlates with Gleason score and pathological stage,34, 35 promotes tumor invasion and metastasis,36 is involved in resistance to enzalutamide37 and Doc.38 Here, we found that CD4+ T cells might affect PCa chemosensitivity through CCL5 activation of STAT3 via upregulation of STAT3 phosphorylation. Here, STAT3 is linked to neoplasm.