My main motivation is to get proper highlighting for HCL files but recent releases of PrismJS have also support for CMake syntax which I'm guessing might interest some people.
The upgrade is however not straightforward: we are using a package called prism-languages to add the languages to hightlight into PrismJS, this was already not really needed when PrismJS was introduced and it now crashes on recent version PrismJS [0].
[0]
https://github.com/survivejs/prism-languages/issues/2