As with the rest of Apple computers that add the new T2 chip inside, the possibility of install a version of Linux or a version later than Windows 10 using BootCamp in them it becomes an impossible task.
Many will think that installing Windows on a Mac is "a sin" but it was a possibility that was opened at the time that Apple computers began to use Intel processors. Right now with the incorporation of T2 chips and its Secure Boot, you cannot install anything that is not certified and signed by Apple.
To install Windows you have to disable system security
This is something that we have already talked about previously in I'm from Mac, but we repeat that the only way to install Windows on these new Macs with the T2 is with a version of Windows 10, and disabling system security so that the disk can read the Microsoft Windows certificates that are assigned to it. In this case it will help Windows to boot, but In the case of wanting to use Linux, things are not looking good at all and you cannot directly.
The security of the T2 chip is interesting for users but it makes reading the disk a totally impossible task for other systems, which paves the way for not allowing other systems to be installed on our MacBook Air or Mac mini. This also happens in the not so new iMac Pro launched by Apple, which also mount this T2 chip inside.