Axion and ALP miniclusters and consequences for cosmology

In this talk I review axion and axion-like particle (ALP) dark matter. I focus on the case that Peccei-Quinn symmetry breaking happens after inflation. This leads to large fluctuations in the axion DM density, with interesting phenomenological consequences. I discuss the formation of axion minicluster and show that ALP dark matter can be constrained by using the sensitivity of CMB experiments to an isocurvature component in the primordial DM density fluctuations.