AGN outflows are believed to play a major role in shaping the properties of host galaxies, by sweeping away the gas and quenching star formation (negative feedback). In this framework our MAGNUM survey aims at investigating in detail the interplay between AGN activity and star formation processes in nearby active galaxies which, due to their vicinity, are the ideal laboratories to carry out such a study. The sample comprises ten famous nearby Seyfert galaxies so far, such as Circinus, NGC 1365 and NGC 4945. Thanks to its unique combination of large field of view and spectral coverage, MUSE at VLT allowed us to map the ionised gas down to ~10 pc in several nebular emission lines revealing ubiquitous kpc-scale outflows, whose properties (e.g. velocity, mass outflow rate, kinetic rate etc...) as a function of distance from the active nucleus were measured. By matching MUSE with Chandra X-ray observations we studied the ionized gas and the outflow kinematics and energetics in its different phases and spatial scales in NGC 1365, and obtained unique insights on the properties of the outflows and of the ISM. Additionally, we recently found evidence of a new mode of star formation, occurring within a starburst outflow itself, as predicted by recent models.