Over the past decade, the field of immuno-oncology has truly come of age and is rapidly evolving. Within just a few years, immunotherapy has been approved as an important treatment option for patients across many cancer types.The ESMO Handbook of Immuno-Oncology was written by specialists in the field and covers many aspects of immuno-oncology, from basic immunology to the current state-of-the-art clinical immunotherapy in different disease types, including management of immune-related toxicities.This comprehensive overview provides a strong base to understand the theory, mechanisms of action, clinical developments and the future of immuno-oncology, and, therefore, is a “must read” for any professional involved in the care of cancer patients.