The mass of ISIS fighters is currently camped out in the Kurdish section of Syria on the Iraq border, with the United States guarding the Euphrates crossing around Dier Ez-Zor.
Makes you wonder why ISIS would flee into an area controlled by the Kurds and exactly what the US military is doing about it, besides preventing pro-Assad elements from going after them.
ISIS previously controlled a LOT more of the now green north (go look up some older maps!!!) & have basically been pushed back into their present enclaves, mainly by the Kurds. The ISIS enclaves are areas they TOOK from the Kurds, and may now be contained by the Kurds, but are certainly not yet “controlled” by the Kurds. To suggest that, or that the Kurds / US are somehow deliberately shielding ISIS from Assad is disingenuous at best.
I would add that I get the impression progress against ISIS has slowed due to the Kurds having to worry about Turkey.
I’d also add that that map is a bit misleading: Inside the blue area and even in the green area are smaller areas that really no one controls. In some desolate places, perhaps no one cares a lot @ present.