"The U.S. and Afghan governments, along with partner countries, remain engaged in combat with a resilient Taliban-led insurgency. U.S. military officials increasingly refer to 'momentum' against the Taliban, however, by some measures insurgents are in control of or contesting more territory today than at any point since 2001. The conflict also involves an array of other armed groups, including active affiliates of both Al Qaeda (AQ) and the Islamic State (IS, also known as ISIS, ISIL, or by the Arabic acronym Da'esh). Since early 2015, the NATO-led mission in Afghanistan, known as 'Resolute Support Mission' (RSM), has focused on training, advising, and assisting Afghan government forces, although combat operations by U.S. counterterrorism forces, along with some partner forces, continue and have increased since 2017."
CRS Report for Congress, R45122