CXCR4 and cancer: Together with knowledge that endocytic dynamics are modulated by cancer (Schmid, 2017; Rosselli-Murai et al., 2018), further mechanistic investigations of how CME and clathrin-independent endocytosis regulate receptor biology is likely to reveal novel signaling mechanism that may provide new therapeutic strategies to selectively target pathogenic GPCR signaling such as CXCR4 in metastatic cancers.