The immune system is highly versatile and changes over time. Immune cell epigenetics plays a critical role in this development. Our research focusses on unraveling the epigenetic modifications that play a role during immune evasion in cancer and in common variable immunodeficiencies (CVID). Our research group is implementing multimodal single cell and bulk omics methods and analysis pipelines to study epigenetic variation, including transcriptomic, chromatin and histone mark changes. In the context of cancer, we aim to see epigenetic differences in systemic immune cells between immune checkpoint inhibitor responders and non-responders. On the other hand, in the CVID cohort we want to link epigenetic differences with the clinical phenotype. Understanding the epigenetic landscape of immune cells offers thus potential for developing novel biomarkers and therapeutic strategies in multiple disseases.