It's the Dier Ezzor pocket that is all but finished.  They are surrounded on all sides by enemies and cannot be supplied, nor reinforced.  They are done.  America is still on the Iraqi side of that pocket, so it's not like air support, etc, is unavailable if required. Over in Idlib, the Isis fighters have been being bused into the area for a couple of years now.   It is the presence of the Turkey backed FSA militias - locals with Turkish leanings, that is giving Assad difficulty.  Many of those troops are actually tribally affiliated, and their loyalties overlap between Isis and FSA.  It's rather hard to say where one ends and the other begins. Turkey doesn't want them bombed.  Assad could kick the hell out of them, but he cannot do so without hitting the Turkish FSA people as well.   So Assad is also forced to try diplomacy when I am sure he would prefer not to do so. Isis is kind of forcing the scenario anyways because they have launched attacks out of that region on Aleppo - this has led to renewed fighting between SAA and Isis in the area.   This is also where Russia is using it's remaining air support ops.     Idlib is also the area where some Western support is still getting through to supply Isis - but many of the foreign fighters are leaving, and it looks like few new ones are coming in.  Slowly Assad is likely to gain control of the region, once he settles negotiations with the local tribes.  The locals are Syrians, and he is trying to get them to lower their arms and rejoin Syrian politics.  For now some groups remain in rebellion.