Klaus Okkenhaug obtained his BSc from the University of Victoria, British Columbia, Canada, and a PhD in Immunology from the University of Toronto. In 1999, he joined Bart Vanhaesebroeck's group at the Ludwig Institute for Cancer Research as a Postdoctoral Fellow, working on the role of p110δ in immune responses. He subsequently joined the Laboratory of Lymphocyte Signalling and Development at the Babraham Institute as a Group Leader in 2003. His main research interests include the role of PI3K signalling in the immune system with particular focus on T-cell activation, differentiation and regulation. In recent years, he has contributed to the description of a new primary immunodeficiency syndrome caused by activated PI3Kδ mutations (APDS) and his group demonstrated that inhibition of PI3K-p110δ in regulatory T cells unleashes a potent anti-tumor response. In October 2017, he joined the Department of Pathology at University of Cambridge as its new Professor of Immunology.