You may owe additional taxes, based on information that you've entered in TurboTax, that you're not aware of.
If
you'll go into "Forms" mode in TurboTax, check to see if you have
Schedules 2 or 4 there.
If you do, click on whichever of those is
present, and you'll be able to see what taxes you might owe in addition
to regular income tax.
