If you filed your 2020 tax return on April 24, 2021, the unemployment exclusion was automatically included in your tax return if you qualified for it. On your copy of your 2020 tax return the exclusion should appear as a negative amount on Schedule 1 line 8, with the abbreviation UCE on the dotted line to the left of the amount. You will not get an additional refund for the tax on your unemployment. You already got the adjustment on your tax return.