Intel Management Engine is a computer within a computer. It is running it’s own operating system, called Minix, and is installed by default on every modern computer with an Intel CPU. This probably makes Minix the most widely used operating system in the world. But unlike Windows, Mac OS or Linux, Minix is completely outside of user control. It cannot be scanned by an antivirus or malware detection software. It can bypass any firewall configuration and has a dedicated network connection that can circumvent the main CPU and the main operating system.

https://themadtruther.com/2019/07/31/how-intel-wants-to-backdoor-every-computer-in-the-world-intel-management-engine-explained/