A new all-sky visible and Near-InfraRed (NIR) space astrometry mission with a wavelength cutoff in the K-band is not just focused on a single or small number of key science cases. Instead, it is extremely broad, answering key science questions in nearly every branch of astronomy while also providing a dense and accurate visible-NIR reference frame needed for future astronomy facilities. For almost 2 billion common stars the combination of Gaia and a new all-sky NIR astrometry mission would provide much improved proper motions, answering key science questions -- from the solar system and stellar systems, including exoplanet systems, to compact galaxies, quasars, neutron stars, binaries and dark matter substructures. The addition of NIR will result in up to 8 billion newly measured stars in some of the most obscured parts of our Galaxy, and crucially reveal the very heart of the Galactic bulge region. In this white paper we argue that rather than improving on the accuracy, a greater overall science return can be achieved by going deeper than Gaia and by expanding the wavelength range to the NIR.
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