  We evaluate dark matter (DM) limits from cosmic-ray antiproton observations
using the recent precise AMS-02 measurements. We properly take into account
cosmic-ray propagation uncertainties fitting at the same time DM and
propagation parameters, and marginalizing over the latter. We find a
significant (~4.5 sigma) indication of a DM signal for DM masses near 80 GeV,
with a hadronic annihilation cross-section close to the thermal value, sigma v
~3e-26 cm3s-1. Intriguingly, this signal is compatible with the DM
interpretation of the Galactic center gamma-ray excess. Confirmation of the
signal will require a more accurate study of the systematic uncertainties,
i.e., the antiproton production cross-section, and modelling of the solar
modulation effect. Interpreting the AMS-02 data in terms of upper limits on
hadronic DM annihilation, we obtain strong constraints excluding a thermal
annihilation cross-section for DM masses below about 50 GeV and in the range
between approximately 150 and 500 GeV, even for conservative propagation
scenarios. Except for the range around 80 GeV, our limits are a factor 4
stronger than the limits from gamma-ray observations of dwarf galaxies.
