My guess is they’ll go back to Syria. Also, the Sunnis in Iraq stood by while ISIS went on a rampage, but by now ISIS has had time to anger them too. So in typical Arab fashion, once ISIS is retreating or vulnerable, the Sunnis will fall on them too to get their glory.
Good, kill them all. Prayers for our troops.
I forgot to add that Abu Bakr al-Baghdadi, the “Caliph” himself, has already left back to Raqqah - a couple of weeks ago, he was strutting around Mosul like a rooster, but now he’s high-tailed it back to Syria.
Yes, he’s a dangerous fanatic with delusions of grandeur - but I doubt he’s a stupid man; hence his departure back to safer territory.