While cheaters are, unfortunately, nothing new to Call of Duty: Warzone, this new cheat will surely set a precedent.
A few days ago, a tool called "Cod Dropper v0.1" was advertised on popular cheating forums. In theory, this application would let you use cheats while playing. However, Activision security researchers found out that a this tool is actually malware. The application can be used by hackers to install and download undesirable softwares.
According to the researchers, "when it comes down to it, the dependencies for a 'genuine' cheat to work are the same as those needed by most malware tools to successfully execute. System protections need to be bypassed or disabled, and privileges need to be escalated to allow the program to run correctly and/or establish persistence."
For further detailes, you can read a report with an in-depth analysis on this site.