Marelli’s career has always been focused on the mechanisms that link immunity to cancer. She had her PhD in Immunology in the lab of Paola Allavena at Humanitas Research Hospital in Milan, Italy. During her PhD she unveiled the role of macrophages in controlling the balance between homeostasis and inflammation in the gut and their impact on colorectal cancer development. After completing the PhD, she moved in the UK for a short postdoc experience in Prof. Segal group at University College of London. Afterwards, she was appointed with a postdoctoral position at Queen Mary University of London Barts Cancer Institute.

Her project focused on immunotherapy using a new oncolytic virus specifically designed in order to increase its power against the tumour by activating the immune system. In 2019, she have been awarded with an AIRC fellowship for Italy that allowed her to move back to Italy in the laboratory of Diletta Di Mitri at Humanitas Research Hospital Centre.

Her current project takes advantage of whole-genome CRISPR editing to unveil the mechanisms behind innate immunity activation in prostatic cancer to develop immunotherapy that could be useful for patients.