Peter Dreger, MD, Heidelberg University Hospital, Heidelberg, Germany, discusses treatment strategies that can be used in patients with B-cell lymphomas relapsing following allogeneic hematopoietic stem cell transplantation (alloHSCT). Prof. Dreger describes how radiotherapy alone or in combination with pathway inhibitors is an option for patients with aggressive B-cell lymphomas and large B-cell lymphomas that are insensitive to immunotherapy. He also comments on how biopsies can help identify druggable targets and how patients with other B-cell lymphomas, such as follicular lymphoma, can benefit from immunotherapy. This interview took place at the 2021 Relapse After HSCT² Workshop in New York, NY.