I am grateful to A. Hayday for insightful ideas and support, and to F. Balkwill for wide-ranging advice and for being an inspiring model for educational activities. I thank all the collaborators that made the exhibit possible and apologize to those I did not name for lack of space. Exhibit’s leading institution: the Francis Crick Institute (FCI); partner institutions: National Research Council of Italy, King’s College London, and the Centre of the Cell, Queen Mary University of London. Funding: FCI, Cancer Research UK and the British Society for Immunology. Funding for research in Di Rosa’s lab in relation to the exhibit: NextGenerationEU-MUR PNRR Extended Partnership initiative on Emerging Infectious Diseases (project no. PE00000007, INF-ACT).