Sepsis is a life-threatening condition caused by the body’s response to a bacterial, fungal or viral infection. Most frequently, it affects adults over the age of 65, children younger than one year of age, people with chronic medical conditions such as diabetes, lung disease, cancer, and kidney disease, as well as those with a weakened immune system. Unfortunately, sepsis is still a common occurrence with an estimated 50 million cases occurring worldwide each year. It is one of the most common causes of death for hospitalised patients in European countries with a high mortality rate of 30-40%. Even though the prescription of antibiotics and the establishment of Intensive Care Units (ICUs) have already greatly reduced the number of sepsis-related deaths, the introduction of an immunotherapy approach is intended to greatly improve the outcome of the disease for those affected. This is where ImmunoSep comes into play. While past studies have promoted a ‘one-size-fits-all’ treatment approach, this multinational project focuses on the exploration of personalised immunotherapy. This takes into account that, although overinflammation and immunoparalysis play a critical role in the physiological processes of sepsis, they manifest differently in individual patients. Therefore, only a precision medicine-based approach for immunotherapy will be able to significantly improve the outcome of this severe clinical condition. ImmunoSep intends to open a new way of treating severe infection through personalised treatment with the potential to represent a qualitative leap in sepsis outcome and to provide a basis for future precision-medicine in immune-based disorders.