Abstract: The discrepancies between Cold Dark Matter (CDM) simulations and observations appear to be solved when baryonic physics are invoked. However, one seems to persist, the ‘diversity problem’ in the dwarf galaxies rotation curves. Surveys such as SPARC, THINGS and LITTLE THINGS show that while some galaxies have slowly rising rotation curves (i.e. ‘cored’ with a substantial inner mass deficit relative to LCDM), others have steeply rising rotation curves (i.e. ‘cusped’). Where do the highest-resolution LCDM simulations stand when trying to solve this problem? In this talk I will answer this question, and discuss an alternative framework to CDM, self-interacting dark matter (SIDM). SIDM is a promising scenario that may alleviate all small-scale problems. It considers the possibility of DM particles interacting non-gravitationally with each other, experiencing collisions that transfer heat towards the central regions of galaxies. It can easily produce cores in dwarf galaxies, but when the number of DM particles interactions is sufficiently large, it can produce an opposite effect, turn cores into cusps, that naturally leads to a diversity in the galaxies rotation curves. I will show this and introduce the TangoSIDM project, a recent simulation suite project that models cosmological hydrodynamical simulations of structure formation in a SIDM universe. I will show results from the TangoSIDM simulations and discuss the range of the SIDM parameter space that can solve the small-scale problems of the local Universe.