Cancer immunotherapy has now transitioned from experimental idea into the standard of care for several cancers. With the 2018 Nobel Prize in Physiology and Medicine being awarded to two outstanding scientists who discovered and recognised the potential for immune checkpoint blockade, this Special Edition on Immunotherapy is a celebration of the successes and ongoing challenges in this field. Curated by Dr Niels Halama (University Hospital Heidelberg, Germany), the articles featured cover several facets of the immune landscape, from the local immune microenvironment to the array of therapeutic possibilities that immunotherapy is heralding. This Special Edition on Immunotherapy contains a selection of articles, commissioned content and videos that provide valuable insight into immunotherapy design, stratification and toxicity management.