Extended scalar sectors at future colliders.

After the discovery of the Higgs boson in 2012, particle physics has entered an exciting era. An important question is whether the Standard Model of particle physics correctly describes the scalar sector realized by nature, or whether it is part of a more extended model, featuring additional particle content. A prime way to test this is to probe models with extended scalar sectors at future collider facilities. We here discuss such models in the context of high-luminosity LHC, a possible proton-proton collider with 27 and 100 TeV center-of-mass energy, as well as future lepton colliders with various center-of-mass energies.