Many (many) years ago, perfumers relied on a musk compound extracted from the glands of the male musk deer for it’s uplifting, fixative qualities. As people became more concerned about animal welfare, it became less ok to use animal derived musk in perfume. Nice, progress.
In recent decades, the use of deer musk has all but ceased in the fragrance industry. However, because making perfume without musk is like cooking without butter (quote, unquote Abel Nose Isaac Sinclair). In its place, synthetic musk has become extremely widely used (estimated in more than 99% of perfume on the market). Why are we not happy with this? Synthetic musk is also widely acknowledged as a toxin to humans and the environment (read more here).