there were about 20 females who broadcast in English over Japanese radio services during WWII. None of them used the nickname "Tokyo Rose." Most of them were Japanese, but the most famous was Iva Toguri, and American who broadcast under the name Orphan Ann.
Iva Toguri was convicted of treason and did six years of a 10-year sentence. She was pardoned in 1977.
No one has been executed for treason since the Civil War. The few convictions since seem to draw about 10-year sentences. Most people using the word treason are not using it in its American legal sense.