Why am I seeing: You have Additional Medicare Tax (Form 8959), and that's just one of the reasons the IRS requires you to file Form 1040

[LindaB1993]

It seems you may be liable for the additional medicare tax  because of your income level.  This additional tax is reported on Form 8959.

A 0.9% Additional Medicare Tax applies to Medicare wages, self-employment income, and railroad retirement (RRTA) compensation that exceed the following income threshold amounts based on filing status: $250,000 for married filing jointly; $125,000 for married filing separately; and.

When a portion of an individual's wages will be subject to the additional tax, but earnings from a particular employer do not exceed the $200,000 threshold for withholding of the tax by the employer, the employee is responsible for calculating and paying the additional 0.9% Medicare tax.