Former Ukraine Ambassador Marie Yovanovitch has retired from the State Department, NPR first reported. The career diplomat remained on payroll since she was ousted from the department last year, per NPR.

Why it matters: During her closed-door deposition before House impeachment committees, Yovanovitch testified that President Trump's lawyer Rudy Giuliani led the smear campaign that led to her firing. Her ouster and testimony were key events leading to Trump's impeachment in the House.

State Department officials did not immediately respond to a request for comment.

Go deeper: First casualty of impeachment war