A: Because Cheat Engine contains a "kernel driver." To Windows Defender, this looks like a rootkit. You must add an exclusion folder for your CE directory before extracting.
"Ghost in the Hex"
Cheat Engine v7.4 Portable by Devint: An In-Depth Look Cheat Engine v7.4 Portable by Devint cheat engine v7.4 portable by devint
Searching for a specific blog post titled suggests you are looking for a pre-configured, "no-install" version of the popular memory scanner and hex editor. A: Because Cheat Engine contains a "kernel driver