CCL5 and neoplasm: Similarly, we hypothesized that the chemokines CCL2 and CCL5—which are pro-metastatic chemokines that promote tumor cell invasion [41,42,46,48,64,65,66,67,68,69,70,71] and act mainly through the Gαi-signaling receptors CCR2 and CCR5, respectively [63,72,73]—also contribute to increased invasion of WT-PD-L1-MDA cells.