The U.S. will be withdrawing about 2200 troops from their total of about 5200 overseas. Troops were deployed in order to defend against the Islamic State militant group, but the U.S. is confident that Iraq has obtained the ability to defend mostly by themselves. Marine General Frank Mackenzie, the head of U.S. Central Commands says “The U.S. decision is a clear demonstration of our continued commitment to the ultimate goal, which is an Iraqi Security Force that is capable of preventing an ISIS resurgence and of securing Iraq’s sovereignty without external assistance.”
Source: https://taskandpurpose.com/news/us-military-reducing-troops-iraq