I filed my taxes on January 18th and it does not show in the IRS website still as of today, January 27th. Why??
Because today in the Untied States it is Sunday, January 26, 2020
Your tax returns will remain Pending until the IRS starts receiving tax returns.
Go to this IRS website for the official start date - https://www.irs.gov/newsroom/irs-opens-2020-filing-season-for-individual-filers-on-jan-27
Your e-filed return is still in pending on the server because the IRS will not begin to accept/reject/process returns until January 27. Only a few returns were accepted early in a test batch. Everyone else has to wait.
So watch your emails and spam folder to make sure you know after Jan. 27 if your return was accepted or rejected.