The DeepCore detector is a densely instrumented sub-array of the IceCube Neutrino Observatory designed to observe atmospheric neutrino interactions above 5 GeV via Cherenkov radiation in the Antarctic ice. At these energies, Earth-crossing muon neutrinos have a high chance of oscillating to tau neutrinos. These oscillations have been previously observed in DeepCore through both muon neutrino disappearance and tau neutrino appearance. While DeepCore is able to measure oscillations with a precision comparable to accelerator-based experiments, it also complements accelerator measurements because it probes longer distance scales and higher energies, peaking above the tau lepton production threshold. Here we discuss the IceCube Collaboration’s latest analyses of the atmospheric neutrino oscillation parameters using 8 years of data. These analyses benefit from more data compared to previous publications, as well as significant improvements in background rejection, reconstruction techniques, modeling of systematic uncertainties, and particle identification.