Gmhck.cc is a page that offers to hack certain applications, in this case Free Fire. As its name says, it is a "game hack", which is supposed to allow you to obtain an infinite amount of diamonds, but the truth is that it can be something that can become a lie.
This third-party app can end up giving you a negative experience in and out of the game, as what it offers is totally a scam.
What this page really does is steal your money and balance on a monthly basis. The page is true that it offers to hack some applications and games, as well as Free Fire, but it really is a lie. Trying to download this software is a total scam, it is just a way to get your money stolen on a monthly basis.
The recommendation is that you do not fall into traps like these, because if you have an account where you have advanced a lot and have a high level, you could lose all your progress, and as if that were not enough, by linking your account you would also start to lose a lot of money.
Gmhck.cc is one of the biggest scams that can exist within the video game community, it is something that can only give you a hard time.
Can I get banned if I use gmhck.cc?
The answer is yes. Free Fire has banned a large number of accounts for the same reason, or for similar reasons. In fact, the number of accounts that have been banned for using hacks exceeds one million. Doing this can end very badly for you, since you would lose everything you have achieved in the game, and you will not be able to enter any other game.
Your account would be suspended permanently for trying to use cheats, Garena's policies regarding the use of external applications that modify the game are quite severe.