There is currently no plan to do this, but blender is open source. It’s possible for an outside developer to make a metal version of cycles in the future.
Apple has also deprecated openGl. This could keep blender from even running on macOS if the next release doesn’t include it, so the foundation’s plan is to slowly migrate to using vulkan. That way mac users can get blender working through moltenVK.
You might be interested in these threads concerning this: