Cemu Mac as of now is not in development or has ever been released for Mac. This is mainly because Cemu works on OpenGL 4.0 which isn’t that efficient on Mac. This is one of the reasons why there hasn’t been a Cemu Mac already but the developers have made it clear they intend to release Cemu on Mac after they have worked out the bugs and gotten it out of the beta phase.
According to the developers, “Multi-platform support is planned and so far many development decisions have been in favor of supporting multiple platforms. (E.g. choosing OpenGL over DirectX for rendering) But currently there thousands of other little things that need to be done before work on ports can start.”