Windows likes to pretend it’s the only OS in the world so it can overwrite the bootloader and you lose access to the Linux install.
But if you use separate disks for each there’s a simple solution if your BIOS has a quick boot selection: install each bootloader on its respective disk and use the BIOS selector at boot.
Alternatively, install the Linux bootloader on the Linux disk; it will autodetect Windows and offer it as a boot option, but Windows won’t be aware of Linux. In BIOS you set Linux as permanent boot disk in this case.