Long considered the missing link in the energy transition, hydrogen is now seeing its uses become clearer, with a key role in the sectors that are most difficult to decarbonize, such as heavy industry and long-distance mobility. However, the transition to low-carbon production comes with many technological, economic, and geopolitical challenges, in addition to major environmental and regulatory issues. This session will provide an overview of these interdependent dimensions to better understand the conditions necessary for the deployment of a hydrogen ecosystem, before opening the discussion on a possible future breakthrough: the exploitation of natural hydrogen.