The IceCube Neutrino Observatory is a cubic-kilometer Cherenkov neutrino detector deployed in the glacial ice at the geographic South Pole. DeepCore, its denser sub-array, lowers the energy threshold for neutrino detection to less than 10 GeV. In recent years, IceCube became one of the leading instruments measuring the neutrino mixing parameters in the atmospheric sector. In addition, its data are used to search for new physics beyond the standard three-neutrino mixing. This talk discusses the most recent neutrino oscillation results from IceCube and future of in-ice measurements of fundamental neutrino properties.