CXCR4 and gastric cancer: In addition, a few studies have demonstrated that the combined blockade of CXCL12-CXCR4 and PD-1- PD-L1 pathways could provide survival benefits by regulating the TME of various solid tumors (Feig et al., 2013; Wu et al., 2019; Zeng et al., 2019; Seo et al., 2019) shedding light on CXCR4/PD-1-targeting combination therapy in GC.