MacOS and Linux are completely different systems and have their own kernels that are not compatible with each other. MacOS has its roots in UNIX, and Linux is an independent development.
The microkernel-based BSD UNIX operating system MacOS has its own driver architecture, window manager, and display subsystem. Called the "Darwin Microkernel", it was developed in 1985 by John Gilmore and Rick Kern to create a standardized operating system that was not tied to a specific hardware family.
MacOS has something to do with the free operating system FreeBSD because the macOS kernel was originally based on it. Even today, FreeBSD programs can be installed and used on a Mac without any problems, which shows the compatibility of both systems.
Linux is a monolithic kernel with no UNIX ancestry, but it offers a very UNIX-like POSIX environment thanks to GNU libraries and utilities. Linux was a completely independent project. The first GNU/Linux distributions appeared in 1992, although the Linux kernel was not developed until 1991, even though the GNU userland tools had been in development since 1983.
The POSIX conformance of Linux and macOS is a pleasant coincidence. This means that server software and programming languages can be transferred without problems (Ruby, Python, gcc, clang, Erlang, and many others).
With the exception of case sensitivity on macOS, the file system conventions are almost identical, although they require a little more care to avoid problems. Any program that works on a Linux system, or almost all GNU software, is also available for macOS.
