Over the last 10 years, technological advances in molecular biology enabled a more accurate genomic characterization of tumors. For each tumor location, this led to the identification of subgroups with similar molecular characteristics. This identification allowed the development of targeted therapies and thus to improve the patient prognosis. This molecular characterization has also revealed the tumor heterogeneity. It may be the cause of treatment resistance and therefore of relapses. Additionally, tumor cells are in constant dialogue with their microenvironment composed of different immune or non immune cells. This microenvironment is now targeted in cancer treatment.