What cells are part of the immune system? Where are they found in the body? How do you make a vaccine and how long will it take during the ongoing pandemic of COVID-19? Understanding basic immunological concepts is more important than ever: It can help understand how immunology research works and why it is so important. With many research projects in the field of molecular immunology and immunological signalling CIBSS wants to make this field more accessible to the public: the cluster invited two investigators Jun. - Prof. Katrin Kierdorf and PD Dr. Susana Minguet to contribute to the day of immunology on the 29.4.2020 with videos explaining to people outside of research how the human immune system works.