I suppose the official relationship between the USA and Lebanon's Army meant this could happen, plus some of the stranger SOF deployments in Syria between rival factions was a sign.

From an Israeli newspaper and their headline:
U.S. Special Forces in Lebanon Prepare to Fight ISIS – Alongside Hezbollah? The Americans are training with the Lebanese army, while Hezbollah is gearing up to fight ISIS.
Link:http://www.haaretz.com/amp/us-news/1.805446