Over the last 6 years at the German Cancer Research Center (DKFZ) I focused my research on Chronic lymphocytic leukemia (CLL). My work aimed at identifying molecular mechanisms involved in the cross-talk between immune cells and cancer cells in the tumor microenvironment. Using state-of-the-art technologies such as single-cell RNA-seq, mass cytometry, immunofluorescence microscopy and flow cytometry, as well as in vivo mouse models, I performed an in-depth characterization of the T cell landscape in CLL. I was able to describe novel mediators of tumor immune escape and candidate targets for the development of novel therapy approaches. For example, I identified the cytokine interleukin-10 as a relevant molecule for the T cell-mediated anti-tumor immunity in CLL. In addition, I found that the lymph node tissue in CLL patients constitutes a unique niche where several regulatory T cell subsets as well as T cells with an exhausted phenotype accumulate, uncovering a mechanism of cancer immune-escape. Moreover, I described the TIM-3 ligand Galectin-9 as a novel immunotherapy target for CLL. In order to develop such complex multilayered studies, I extensively cooperated with academic partners and clinicians in Germany and abroad, thereby fostering my project management and collaborative skills. The outcome of all this work has been the publication of 7 peer-reviewed scientific articles in addition to two that are currently under revision process. During the last three years I extended my teaching skills by supervising two master students and one PhD student, training them in numerous laboratory techniques as well as guiding them in the development of their thesis projects. In addition, I had the opportunity to present and defend my research through oral presentations as well as posters at numerous international conferences and meetings.