How to stop hacker?

There's nothing other than reporting that you can do.
If you're talking about CS:GO or a similar game (I think it's the only one with this so far) -- The Overwatch feature where you can get hackers banned yourself and help sort out the community that way. The more people that replace the job of the well and broken VAC, will help revive the community and in turn earn Valve more money to spend on NOT IMPROVING VAC, beacuse hackers have to buy the game over and over again. Ever wonder why CS:GO is never really on sale? It's because hackers would buy the fuck out of the game and stockpile it for later, they can earn some massive bank that way if they know where to sell...