We have the mac tag without any wiki and 127 questions and the osx tag with a wiki and 367 questions (and the synonym apple). IMHO we don't need both tags (I don't see anybody discussing e.g. problems with TeXLive on Linux on Apple systems).
I've merged the tags here, leaving mac as the 'master' (as noted, MacOS X is being replaced by Apple by 'macOS').
To help people find tags with a few letters, I feel some interest in hyphenated tags. And to avoid tag recreation, would something like apple-mac-osx suit your needs?