CXCR4 and colorectal cancer: CXCL12 and PD-L1 expression were reduced by Pep R treatment possibly through impairment of stromal/immuneregulatory cell recruitment [12] and/ or transcriptional regulation [40] while CXCR4 and PD-L1 expression were reduced in tumors treated with anti-PD-1 + Pep R. It was previously demonstrated that CXCR4 antagonists reshape TME favoring access of T effector and reducing the immunoregulatory cells in a model of pancreatic cancer [11], hepatocellular carcinoma [41] colorectal cancer [14] and ovarian cancer [13].