It appears Putin is secretly and illegally using private military contractors to fight in Syria. The contractor company is called Wayne and it's illegal under Russia's constitution.
They are basically using g them as meat shields in front of the Syrian army on the ground. It's estimated 600 to 1k of the poorly trained fighters have died so far.
The same contractor company was doing much of the fighting in Ukraine as well.
Revealed: Russia's 'Secret Syria Mercenaries'