Inverse Seesaw, dark matter and the Hubble tension
  We consider the inverse Seesaw scenario for neutrino masses with the
approximate Lepton number symmetry broken dynamically by a scalar with Lepton
number two. We show that the Majoron associated to the spontaneous symmetry
breaking can alleviate the Hubble tension through its contribution to $\Delta
N_\text{eff}$ and late decays to neutrinos. Among the additional fermionic
states required for realizing the inverse Seesaw mechanism, sterile neutrinos
at the keV-MeV scale can account for all the dark matter component of the
Universe if produced via freeze-in from the decays of heavier degrees of
freedom.
