In 1994 he moved to Seattle, WA where he worked on tumor immunology and immunotherapy, studying T cell ignorance of tumor antigens and the role of T cell costimulation in mouse models of cancer. His studies of that time on CD137-mediated co-stimulation of curative antitumor immune responses have received much attention by the immunotherapy of cancer community and have resulted in therapeutic agents undergoing phase II clinical trials. Since 1998 he returned to Navarra University where he currently serves as a full professor of Immunology at the Clinica Universidad de Navarra (where he heads the department) and at the investigation centre CIMA. His current areas of research are focused on from bench to bed side translational research with cell, gene and monoclonal antibody-mediated strategies of immunotherapy for cancer. Dr. Melero has authored over 180 indexed publications attaining an h factor of 45 with over 6,000 citations in the biomedical literature. He has been awarded the BIAL Medicine Award, Conde de Cartagena Award from the Royal Academy of Medicine, Doctor Durantez LAIR Foundation Award and a CRI research award.