This is an interesting take considering Linux is Unix-like and macOS is technically a BSD derivative. I don’t think macOS will ever have a Linux syscall translation layer/subsystem (WSL1) nor a lightweight VM with special integration (WSL2) but you can do sort of similar things in third party software, I think. Docker for Mac is using the native VM framework and includes a filesystem integration called osxfs, but despite mentioning the source code in documentation it does not appear to be open source at this time?
Exactly. It really doesn't need a syscall translation layer anyway given its Unix + BSD and POSIX foundations. Although this open-source project [0] does exist for macOS but it looks like its inactive.