The Maunakea Spectroscopic Explorer (MSE) is a proposed major modernisation of the 3.6-m Canada-France-Hawaii Telescope into a 11.25-m aperture, 1.52 square degree field of view telescope. MSE is a fully dedicated facility to carry out multi-object spectroscopy surveys. MSE will provide a spectral resolution performance of R∼2,500 - 40,000 across the wavelength range of 0.36 - 1.8 μm. The overall MSE project is presented in these SF2A2019 proceedings by N. Flagey (see also http://www.cfht.hawaii.edu/), here I outline the context and the challenges of MSE with respect to evolution and formation of galaxy populations.