Started with protests in Daraa in 2011, the Syrian conflict rapidly turned into a war with a number of foreign powers supporting various militant groups (including al-Qaeda-linked) against the government of Bashar al-Assad. Since then, the country has been a point of instability in the Middle East.
Russia began a military intervention in Syria in 2015 after an official request by the Syrian government for military help against militant groups.This allowed the Syrian government to survive and to regain initiative in a battle against Hayat Tahrir al-Sham (formerly Jabhat al-Nusra, the Syrian branch of al-Qaeda), ISIS and other militant groups.
If SDF, Turkey join Syria keep their differences and greediness a side and come together and fight against terrorists like ISIS and Al-Qaeda then they can liberate the entire Syria land very fast and easily with minimum casualties but Turkey and SDF fight for their own individual benefits to take land from Syrian nation and control it without care of mass human casualties in SDF and Turkey army.
If SDF, Turkey join Syria keep their differences and greediness a side and come together and fight against terrorists like ISIS and Al-Qaeda then they can liberate the entire Syria land very fast and easily with minimum casualties but Turkey and SDF fight for their own individual benefits to take land from Syrian nation and control it without care of mass human casualties in SDF and Turkey army.