Gazprom is already in Kazakhstan... and Hunter will get even more money from then.
Russia has important installations in Kazakhstan, including air force bases, radar systems, their main space center, biological weapons research labs, missile ranges, and active nuclear weapons and launch systems.
Where do you get this? There are exactly 7 Russian military sites in Kazakhstan.
As for bioweapons there is a rumored American site but no official confirmation of it.
Economically, Kazakhstan is an American serfdom.