Modern cosmology is at a crossroads.  The standard LCDM model, while incredibly successful, faces a series of persistent challenges and "tensions" between key datasets.  The most prominent one is on today’s expansion rate (H_0 tension) but others have emerged on the late redshift expansion potentially calling for a time dependent dark energy.  These tensions may suggest either new physics or unresolved systematic errors.  This places us at a crossroads, where the lack of a robust concordance model challenges our ability to interpret precision cosmology, key to address some open questions in particle physics.

Simultaneously, we are in an era of unprecedented data flow.  Initial results from DESI, mature analyses from ACT and KiDS, and paradigm-challenging discoveries from JWST (such as the "Little Red Dots") provide a complex, and potentially contradictory, picture of the cosmos.

This workshop is motivated by the urgent need to move beyond single-tension discussions. We must synthesize these new, multi-probe datasets and theoretical ideas into a consistent global picture. The workshop will bring together experts in theory, observation, and computation to evaluate where concordance remains robust, where it breaks down, and how the next generation of surveys and theoretical tools can close the gap.

There is no registration fee for this workshop, and a remote connection will be possible. Registration will open in the next weeks.Invited speakers and panelists:Gagandeep Anand (Space Telescope Science Institute) Patricia Diego-Palazuelos (Max Planck Institute for Astrophysics) Georges Efstathiou (University of Cambridge, Institute of Astronomy) Willem Elbers (Durham University) Mathias Garny (Technical University of Munich) Francisco-Shu Kitaura (Instituto de Astrofísica de Canarias) Julien Lesgourgues (RWTH Aachen University) Meng-Xiang Lin (Simon Fraser University) Azadeh Moradinezhad Dizgah (CNRS, LAPTh Annecy) Rohan Naidu (MIT) Anna Maria Porredon (CIEMAT) Mickaël Rigault (IP2I Lyon, CNRS / Université Claude Bernard Lyon 1) José Alberto Rubiño Martín (Instituto de Astrofísica de Canarias) Alessio Spurio Mancini (Royal Holloway, University of London) Licia Verde (ICREA / Institute of Cosmos Sciences, University of Barcelona) Francisco Villaescusa-Navarro (Simons Foundation)Organisers:Matteo BragliaAndrea CaputoValerie DomckeMiguel EscuderoRicardo Genova SantosLaura HeroldMatthew Joseph LewandowksiVivian Pouilin

This TH Institute is supported by UNDARK and is funded through the Widening participation and spreading excellence programme (project number 101159929).