Cell-to-cell communication guarantees homeostasis in a multi-cellular organism. Cancer-to-microenvironment communication sustains malignant growth and dissemination. Whereas the accumulation of mutations is at the origin of malignant cell transformation and neoplasia onset, the interaction between cancer and the surrounding stroma, specifically immune cells, influences the balance between tumour regression and tumour progression. To study how the interaction between cancer and stromal cells is disadvantageous or beneficial for tumour progression, the use of a transparent in vivo model bears important research potentials. Zebrafish has been increasingly used as animal model to study tumour biology. The use of transparent zebrafish embryos, with fluorescent endothelial and immune cells, allows the visualization of cell-to-cell interaction, among host cells themselves and between zebrafish stroma and implanted human cancer cells. Here, we summarise our findings on the role of CXCR4 signalling in tumour progression, considering its signature both on cell autonomous and host dependent mechanisms. Finally, we address the translational impact of targeting CXCR4 signalling in cancer and the tumour microenvironment for the treatment of metastatic cancer.