Earlier quoted context omitted.
Yeah, Managed C++ and C++/CLI don't exist.
I was careful to say "unmodified." C++/CLI is hardly that. It's also not at all sandboxed the way wasm is. Why the chip on the shoulder?
With /clr:pure (which produces CIL only, although it is allowed to use memory-unsafe features like pointers), the entirety of ISO C90 is supported on CLR, with the sole exception of setjmp/longjmp.
C++/CLI adds language extensions that allow one to interact with the CLR object model from C++ code. It is only needed if you need to call into the .NET standard library, or other managed libraries - i.e. if your C code is not portable to begin with.