The tumor microenvironment is an important modulator of malignant growth. A deep understanding of the complex relationships occurring at the tumor site among stromal cells, immune cells, and soluble factors could provide important information on the recruitment of immune cells and the possible impairment of their anti-tumor properties. Elucidating the complex network in the tumor microenvironment can be crucial for understanding the mechanisms of tumor escape from immune recognition, and for developing new therapeutic strategies