The LIFE initiative has the goal to develop the science, the technology and a roadmap for an ambitious mid-infrared nulling interferometer space mission that will allow humankind to detect and characterize the atmospheres of hundreds of nearby extrasolar planets including dozens that are similar to Earth. Given the recent outcome of ESA’s "Voyage 2050" process and the corresponding recommendations from the ESA Senior Committee, the direct detection of the thermal emission of temperate terrestrial exoplanets is given very high scientific priority in ESA's future science program and is considered as a candidate theme for a future L-class mission. We provide an overview of the current mission concept and summarize the unique discovery space for a large mid-infrared exoplanet mission with specific focus on the detection of atmospheric biosignatures.