Tumors establish resistance to immunotherapy by regulating T_regrecruitment via CCR4

CPI upregulates CCL17 and CCL22 expression in tumors and increases T_reg migration into the TME. Pharmacological antagonism of the CCR4 receptor effectively inhibits T_reg recruitment and results in enhanced antitumor efficacy either as single agent in CCR4 ligand^high tumors or in combination with CPIs in CCR4 ligand^low tumors.