MacTeX is a redistribution of TeX Live with a Mac-specific installer, TeXShop, and a few other Mac-only extras. See https://tug.org/mactex/ and https://ctan.org/pkg/mactex for more. Also https://ctan.org/pkg/mactex-basic for the BasicTeX distribution, a severely cut-down, but still functional, version of MacTeX. Also https://ctan.org/pkg/mactextras for the auxiliary distribution here of software not included in MacTeX.