Cells in the tumor microenvironment (TME) of diffuse large B-cell lymphoma (DLBCL) show enormous diversity and plasticity, with functions that can range from tumor-inhibitory to tumor-supportive. The patient’s age, immune status, and DLBCL treatments are factors that contribute to the shaping of this TME, but evidence suggests that genetic factors arising principally in lymphoma cells themselves, are among the most important. Here we review the current understanding of the role of these …