I believe the Russians will send troops into Kosovo.
Putin may send troops, but i just don’t see how logistics are going to support anything more than just a symbolic number of troops. As someone said earlier, the USSR isn’t around anymore, there are a number of nations that stand bwtn Russia and Serbia, not to mention Serbia is landlocked. So unless Putin is going to airlift some troops I don’t see how they get there.
I suppose if he was really serious he could send a few tank divisions thru Romania and into Serbia . . . but i’d rather not think about how that would play out