Adoptive T cell therapy, which employs the patient's own cells as a weapon, is considered a breakthrough in the treatment of cancer. However, the production of such immunotherapy products lacks harmonisation with clinical studies. The EU-funded T-OP project aims to bridge this gap by bringing together interdisciplinary teams of scientists working in cell therapy, immunology, protein engineering and bioinformatics alongside large and medium-sized enterprises. The scientific work will focus on cytokines and their role in the therapeutic outcome of adoptive cell therapy, aiming to determine the optimal combination. The project's results will lead to the development of safer and improved immunotherapeutics.