Seems it has the necessary integration points to run CMake builds as an external command. The same way you could build Make, Autotools, Meson or Bazel projects from CMake with the necessary external command plumbings.

Obviously both fille the same purpose of being a build system, though Bazel is also a build executor not just a generator. Integration would mean either adding BUILD language support to CMake or vice-versa, but you wouldn't get the particular benefits of either this way.