CCL1 and liver cancer: To further confirm that the immunosuppressive function of TI-tregs is modulated by CCR8, CD8+ T cells labeled with carboxyfluorescein succinimidyl ester (CFSE) were co-cultured with TI-Tregs isolated from H22 liver cancer tissues, and after incubation of the co-culture with murine CCL1 in the presence or absence of IPG0521m, CD8+ T cell proliferation was measured.