Carsten Niemann, MD, PhD of Rigshospitalet, Copenhagen, Denmark, provides an overview of what we are learning about chronic lymphocytic leukemia (CLL) treatments and the microenvironment. During treatment, for instance with idelalisib, clinicians need to be very cautious about infections; there is a rapid transfer of research data into clinical practice. Dr Niemann notes that from his perspective, this is just the first steps of understanding how the interaction with the microenvironment actually impairs the immune function in some patients. Understanding both of the impacts of different treatments on the microenvironment, but also the disease itself will make it possible to design individual, tailored treatment. It is known from a previous study published earlier this year, that hypogammaglobulinemia by itself does not identify patients who will develop infections, it actually identifies patients at greater risk of an aggressive disease. Therfore, markers are needed in order to identify patients who need say, prophylactic antibiotics or immunoglobulin substitutions. Dr Niemann concludes by noting that in the coming years the multitudes of different dimension of data will be compiled together to help build new pattern recognition algorithms. Recorded at the 2016 International Workshop of the German CLL Study Group (GCLLSG) in Cologne, Germany.