What happened in 2014 that may be ongoing Civil War in Syria even more complicated

In 2014, the rise of the Islamic State of Iraq and Syria (ISIS) further complicated the ongoing Civil War in Syria. ISIS, a militant extremist group, took advantage of the chaos and instability in the region to seize control of large swathes of territory in both Syria and Iraq. This added a new dimension to the conflict, as various rebel groups, the Syrian government, and international forces all had to contend with the threat posed by ISIS. The presence of ISIS also exacerbated sectarian tensions in the region, further muddying the waters of the already complex conflict in Syria.