Monoclonal antibodies are part of the therapeutic arsenal for eliminating cancer cells. Some make use of the immune system to act and belong to a class of treatment called ‘immunotherapies.’ But how do these antibodies function within the tumor? And how can we hope to improve their efficacy? Using innovative in vivo imaging approaches, scientists from the Institut Pasteur and Inserm visualized in real time how anti-CD20 antibodies, used to treat B-cell lymphoma, guide the immune system to attack tumor cells. Their findings were published in the journal Science Advances on February 19, 2021