CCR1 and gastric cancer: Similarly, HCC-derived CCL15 was shown to induce the infiltration of CCR1+/CD14+ monocytes with multiple immunosuppressive features.508 In gastric cancer, macrophages can secrete CXCL8 which increases their PD-L1 expression while hampering CD8+ T-cell function in the tumor itself.509 Changes in the metabolome of the tumor microenvironment can also affect immune cell function.