Despite the widely recognized importance of the tumour microenvironment the understanding of mechanisms by which immune cells interact with lymphoma cells is still limited. To address this challenge, this project will investigate the infiltration of immune cells in tumour biopsies obtained before therapy initiation. Thereby, different patterns of immune cells between patients can be observed and their impact on the clinical outcome will be investigated. Together with additional characteristics which are obtained in clinical diagnostic procedures these findings have the potential to uncover mechanisms leading to tumour control or progression. This improved biological understanding can help to improve therapy stratification and lead to novel therapeutic approaches.