...All is changing with Windows Subsystem for Linux 2. Instead of emulating the Linux kernel APIs on the NT kernel, WSL 2 is going to run a full Linux kernel in a lightweight virtual machine. This kernel will be trimmed down and tailored to this particular use case, with stripped-down hardware support (since it will defer to the host Windows OS for that) and faster booting.
https://arstechnica.com/gadgets/2019/05/windows-10-will-soon-ship-with-a-full-open-source-gpled-linux-kernel/