Several projects of future colliders are being proposed to follow HL-LHC. Lepton colliders, both circular and linear, are an attractive possibility for studying with exquisite precision the electroweak sector and eventually find discrepancies with respect to standard model predictions that would in turn signal new physics. These machines would also be able to measure the Higgs couplings with a precision of 1% or better. Circular lepton colliders could later be replaced by proton-proton colliders with centre-of-mass energies reaching and possibly exceeding 100 TeV. This would allow to measure the Higgs self-coupling with a precision approaching 5%. Moreover this would open a completely new window at the energy frontier.
In this seminar the various colliders proposed and the detectors foreseen will be reviewed and the current status of the various projects will be presented. Then a review of the physics prospects obtainable with these colliders will be discussed, comparing the possibilities of the various accelerators.