Immunotherapy is changing the treatment paradigm for many types of cancer, with a number of checkpoint blockers and the first cellular therapies on the market. Beyond cancer, immunotherapeutic approaches are undergoing clinical trials for autoimmune conditions and infectious diseases. This Nature conference brings together leading experts from around the globe to discuss a range of immunotherapeutic approaches and the immunological basis that informs these efforts. Besides covering immune checkpoint inhibitors and cellular therapies, sessions will explore vaccination approaches and oncolytic therapy, the role of innate immune cells and their potential for immunotherapy, the effect of the microbiota on immunotherapy and how to exploit immunometabolism to modulate immune responses in cancer and beyond.