Lichens – are complex and dynamic symbiotic entities formed by fungi living together with algal photobionts. They are key organisms for alpine, tundra and taiga biomes. They are famous for their tremendous adaptive ability to a wide range of environments and also to the harshest conditions such as intense UV light, gamma radiation and even Mars-like settings. But lichens Achilles’ heel is the pollution and for many taxa exposure to pollutants is fatal. And yet, some lichens are effective colonisers of heavily polluted sites. However, the underlying mechanism of the lichen adaptation conundrum remains largely unknown. By specifically aiming to understand at the genetic level how lichen photobionts responds to different environmental conditions and to shed light on the photobiont life cycle, I will bring a significant step forward in addressing this key gap in lichen biology. The project builds on my conceptual model - the ‘Suitcase hypothesis’ proposing that the photobiont community assemblage dynamics serve as an adaptive strategy in lichens. Cutting-edge methods, combining molecular ecology, bioinformatics, phylogenetics and metabarcoding, will be employed for the successful outcome of the project. Two successful researchers, from two Nordic Universities will host the project and contribute key knowledge in a two-way exchange. Through its scientific impact, the use of cutting-edge methodologies, the excellent mentorship, the courses curriculum, the outreach activities, and the teaching experience - SUITCASES will set my path towards a successful career at the forefront of lichen research. Through this project, I will address the UN Sustainable Development Goal 15: Life on Land, as well as the Directive 2004/107/EC of the European Parliament and of the Council, which recommends the use of living organisms to complement data and to assess spatial deposition of pollutants.