Strongly lensed quasars with measured time delays provide a one-step way to infer absolute distances and H0 by combining arrival-time differences with detailed mass models of the lens and its environment, a technique now delivering few-percent precision and late-time H0 values that sit close to local distance-ladder results and in significant tension with Planck ΛCDM inferences (Refsdal 1964; Suyu et al. 2017). ΛCDM struggles because these quasar-lensing distances depend sensitively on assumptions about the lens mass profile, line-of-sight structure, and the global FRW geometry, so the agreement of multiple independent lens systems on a high H0 both reinforces the Hubble tension and raises worries that mass-sheet degeneracies or unmodeled environment effects might be conspiring across different systems (Birrer et al. 2019; Wong et al. 2020).