There is no longer any relevant mission for the United States in Afghanistan. Western efforts to determine the future of that country have proven futile.
Though officials with eyes on their legacies caution that an end to the occupation would unravel gains won on behalf of Afghan civilians, calls for deference to humanitarian concerns should ring hollow in the ears of Americans by now. Afghans are suffering terribly because of the war. The supposed humanitarian justification for our interventions has given way to privation, internecine conflict, and prolonged aerial bombardment. President Trump does not believe in the war. Neither do the American people.
There is great superficial appeal in claiming we're advancing the wellbeing of developing countries like Afghanistan. Most Westerners value things like access to education and equal legal standing for both genders.