Explore the fascinating world of dark matter substructure through a 22-minute conference talk delivered by Ioana Zelko from CITA at the Kavli Institute for Theoretical Physics. Delve into the use of gravitational strong lensing in quad lensed systems to probe dark matter, as part of the "Cosmic Signals of Dark Matter Physics: New Synergies" conference. Gain insights into the latest developments in theory, cosmological simulations, and observational capabilities that are expanding the landscape for dark matter discovery. Learn about astrophysical and cosmological constraints on dark matter, efforts to extract dark matter physics from cosmic observables, and potential synergies between particle and cosmology theorists, simulators, and astronomers in the quest to unravel the nature of dark matter.