In this session filmed at the 16th International Workshop on Multiple Myeloma (iwMyeloma) held in Madrid, Spain, Irene Ghobrial, MD, Dana-Farber Cancer Institute, Boston, MA, Charlotte Pawlyn, BA, MBBChir, MRCP, PhD, FRCPath, The Institute of Cancer Research & The Royal Marsden NHS Foundation Trust, London, UK, Lawrence Boise, PhD, Winship Cancer Institute of Emory University, Atlanta, GA, and Paola Neri, MD, PhD, University of Calgary, Calgary, Canada, discuss mechanisms of resistance to treatment mediated by the microenvironment in multiple myeloma. The experts discuss resistance to IMiDs and T-cell engagers and interactions between the tumor and the microenvironment, the role of the stroma in treatment resistance, and comment on how to prevent T-cell exhaustion.