After a devasting counter-offensive that managed to split the opposition-controlled Azaz pocket in two, Islamic State forces across northern Aleppo retreated from the frontlines on 8 June. It is unclear what exactly prompted this withdrawl, but the SDF's ongoing Manbij offensive to the east is probably related. IS forces reportedly regrouped around the town of Dabiq, which holds enormous eschatological importance for the organization (its English language magazine is named for the town). The frontlines of northern Aleppo now resemble the situation weeks ago. It appears that the town of Dudiyan has already changed hands repeatedly. This retreat ended the seige of Mare', which went on for over a week and saw rebels in the town recieve weapons drops from the international coalition, as well as supporting airstrikes. Turkish artillery bombardment of IS-held territory has continued, recently targeting the bordertown of al-Rai.
The day prior to the IS withdrawl, it was announced that multiple opposition groups within Mare' had formed a new alliance, led by the U.S.-backed Liwa al-Mutasem [here is a survey on the faction and its American made and supplied equipment]. It is currently unclear who else is part of this coalition, other than Kurdish FSA outfit Liwa Ahfad Salahaddin, but the leader of Liwa al-Mutasem claims it to be 1,500 strong. This move has reportedly drawn the ire of nationwide Salafist group Ahrar al-Sham [more on Ahrar al-Sham and Salafism here and here], which maintains a small presence within North Aleppo.
For the first time since they took over Tel Rifaat and its surrounding countryside in Febraury, the SDF (both the YPG/J and Jaysh al-Thuwar) have engaged Islamic State forces around the town of Harbul. It was initially reported that they were success in taking Harbul, but this now appears not to be true.
On 10 June, FSA faction Furqat 101 Masha' (101st Infantry Division) announced that it was leaving Furqat al-Shamal (Northern Division)due to "internal problems." The Northern Division was a merger that occurred in December 2015, between the 101st Infantry Division and Liwa Fursan al-Haq, both predominantly active in Aleppo governorate. [more information on the two groups here]