When I was on the Joint Staff on the Bosnia desk, we knew that American contractors were participating in the trafficking of women. That would be Dyncorp, which the US still relies upon for private military contracting. The wiki page is pretty darned instructive and refers to a woman who blew the whistle on Dyncorp, on the International Police Task Force that was supposed to be training the Bosnian police, and on the UN and NATO for ignoring the human trafficking.
The woman, Kathryn Bolkovac, was portrayed in the movie, Whistleblower, by Rachel Weisz that I watched last night. They used a fake name for Dyncorp, but I recognized it easily enough. The movie makes it clear that one of the consequences of deploying peacekeepers, police trainers and others to a post-conflict zone is to create a market for prostitution. There was plenty of organized crime that developed during the war that then took advantage of the demand and provided the supply via girls and women. Indeed, the UN Peacekeepers that preceded the NATO mission did much to enrich the criminals.
While the UN and NATO did not deliberately support human trafficking, they tended to cover it up, apparently, so that their missions would not be tainted. It was certainly the case that individuals serving in these missions employed the prostitutes and even abetted the organized criminals. Truly awful for organizations aimed at helping people to tolerate and even abet the impunity of the criminals.
I guess the upside to a highly kinetic war where there is pretty strict gender segregation might mean that there is less of this in Afghanistan, but I would not bet much on it.