The question is what the significance of the tumor microenvironment is in classical Hodgkin lymphoma. Classical Hodgkin lymphoma is a unique lymphoma in that the malignant cells are heavily outnumbered by reactive cells in the microenvironment. Therefore, it serves as a very good paradigm to study tumor microenvironment interactions in Hodgkin lymphoma and in lymphoma in general. Using the microenvironment as a biomarker, we can learn unique biology, but we can also use the information to predict outcomes in this disease. In the literature, most of the biomarkers are at the moment related to the microenvironment because of its relative abundance compared to the malignant cells.