In this talk, I will discuss what kind of dark-sector physics could explain the recent DESI findings while addressing the Hubble tension without introducing new discrepancies elsewhere. Late-time extensions, including dynamical dark energy and interacting dark-sector models, can significantly improve the fit to DESI and, in some cases, shift the inferred value of H0 toward local measurements, but typically fail to fully resolve the Hubble tension. A complete resolution appears to require additional early-time ingredients, raising the question of whether two distinct modifications are needed, or whether early- and late-time new physics can emerge as different manifestations of the same underlying dark-sector dynamics. I will argue that this is possible in principle, but highly non-trivial to realize.