Galaxy clusters are unique astrophysical laboratories in which the powerful interaction of supermassive black holes with the surrounding intracluster medium, the complex effects of the cluster environment on galaxies, as well as a wide range of non-thermal processes like magnetic field amplification and cosmic ray acceleration can be studied. In addition, clusters form from the largest matter overdensities in the Universe that collapse under their own gravity. Due to their formation from these highest density peaks, clusters provide a large leverage to probe cosmological models. However, to make full use of this potential, the internal structure of clusters and how it affects observational signatures needs to be understood. This meeting will bring together both international experts on this subject and early career researchers to catalyse progress on puzzles like the discrepant cosmology results from galaxy clusters and the primary cosmic microwave background and to help interpretation of a wealth of upcoming, multiwavelength observational programmes, such as eROSITA, Athena, JWST, DESI, Euclid and SPTPol and Advanced ACT.