Rockstar Adds New Anticheat to GTA 5 for PC 9 Years After Release
An anti-cheat called BattlEye from an outside company has been added to Grand Theft Auto V on PC. This may be intended as a test before GTA VI.

Online mode. Unfortunately, it's plagued by cheaters who ruin the fun for others. It appears that Rockstar has taken action and introduced an anti-cheat system to the game in today's update.
BattlEye Anti-cheat in GTA V
We can find information about the addition of a security feature called Escape from Tarkov. So if you are playing any of these games, you should be able to assess its effectiveness.

It's worth noting that this isn't the first security measure of this kind discovered in GTA V. Nearly 2 years ago, Rockstar was expected to eliminate the previous anti-cheat system from the game, which, in the opinion of many players, was ineffective.
However, if you are worried that BattlEye will affect your single-player fun, let me reassure you right away. The GTANet shared information on X that this security feature can be disabled from the launcher level. Of course, if we choose to do so, we won't to the Online mode.
It's hard to say why Rockstar decided to add an anti-cheat now, so many years after the release (counting the console release, GTA 5 just turned 11 years old). This may be intended to serve as a sort of trial run before GTA VI, which will definitely also feature an online mode. The developers may want to test the effectiveness of BattlEye in this way before deciding to implement it in the installment.