Why? The IRS will have the W-2 they receive from your employer and expect to see that W-2 entered on the federal tax return, Form 1040, that you file.
Employers have until 02/01/2021 to provide you the W-2.
The IRS will not be accepting any type of 2020 federal tax return until late January 2021. If you file now the return will just sit on the servers until the IRS opens for filing.
