The observation of neutrino masses remains, to date, the only direct evidence for physics beyond the Standard Model. Cosmology constitutes an extremely powerful arena for testing neutrino properties, including the neutrino mass scale: the latter leaves very subtle correlations both among the the positions of millions of galaxies, as well as among the hot and cold spots of the Cosmic Microwave Background, the oldest light we can see. In this colloquium, I will describe the exciting hunt for the neutrino mass scale and mass ordering from current and future precision cosmological data, highlighting challenges we need to address to reach a robust detection in the coming years.
