Your 2019 refund will not affect your 2020 tax return. But you can't file your 2020 tax return until you have all your W-2s, 1099s, and other tax documents. Your employers have until February 1 to send you your W-2s.
Furthermore, the IRS will not start accepting 2020 tax returns until sometime in late January. They have not yet announced the exact date. TurboTax will let you "e-file" your tax return before then, but your tax return will not really be filed. TurboTax will just hold it until the IRS begins accepting returns. Nothing will be done with it before then. If you submit it early, be aware that you can't cancel it or get it back to make changes or corrections if you find that you made an error or left something out.