If you have become a permanent resident of PA, you should file a Maryland MW507 form with your employer to stop the withholding of MD taxes. You become a permanent resident of PA by your actions, such as changing driver's license, auto registrations, voting registration, establishing social ties etc.
In the year you moved, you would be considered a part year resident of each state and file a part year tax return to both states.
Due to the reciprocal agreement between PA and MD, MD agrees not to tax the wages of a PA resident and vice-versa.
