Did you include it on your 2020 return? You can't skip a year. If you did not include it, amend your 2020 return. If you did include it and it didn't transfer, then just add it in yourself.
Open your TurboTax return, search for capital loss carryover, and then select the Jump to link in the search results.
We'll take you to the screen where you can enter that info from your prior year return.