CCL5 and neoplasm: In support of the active inhibitory mechanism exhibited by PD-L1, we observed a strong negative correlation between PD-L1 expression in the TME and systemic levels of immune mediators related to anti-tumor responses via tissue migration and inflammation including IL-1a, IL-1b, IL-12, RANTES, SDF1a, TNF-a, TNF-b and others (Fig. 7).