The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky selected from WISE and NEOWISE survey data at 3.4 and 4.6um (W1 and W2) collected from 2010 Jan 7 to 2018 Dec 13. This dataset adds two years to that used for the CatWISE Preliminary Catalog (Eisenhardt+ 2020ApJS..247...69E), bringing the total to six times as many exposures spanning over sixteen times as large a time baseline as the AllWISE catalog. The other major change from the CatWISE Preliminary Catalog is that the detection list for CatWISE2020 was generated using "crowdsource" software (Schlafly+ 2019ApJS..240...30S), while the Preliminary Catalog used the detection software used for AllWISE (II/328). These two factors result in roughly twice as many sources in CatWISE2020. The scatter with respect to Spitzer photometry at faint magnitudes in the COSMOS field, which is out of the Galactic plane and at low ecliptic latitude (corresponding to lower WISE coverage depth) is similar to that for the CatWISE Preliminary Catalog. The 90% completeness depth for CatWISE2020 is at roughly W1=17.7 and W2=17.5, about 1.7 mag deeper than in the Preliminary Catalog. From comparison to Gaia, CatWISE2020 motions are over a dozen times more accurate than those from AllWISE. Acknowledging CatWISE2020 in publications: The primary reference for CatWISE is Eisenhardt et al. (2020ApJS..247...69E). Marocco et al. (2021ApJS..253....8M) describes updates for the CatWISE2020 Catalog. Please include the following in any published material that makes use of CatWISE data products: "CatWISE uses data products from WISE, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory (JPL)/California Institute of Technology (Caltech), funded by the National Aeronautics and Space Administration (NASA), and from NEOWISE, which is a joint project of JPL/Caltech and the University of Arizona funded by NASA. CatWISE is led by JPL/Caltech, with funding from NASA's Astrophysics Data Analysis Program."