None, because they typicially open up a larger attack surface than the system would have without them. It’s been like that for a while now. For references, I’d recommend this article from Ars Technica, who reference some very knowledgeable people (including Chrome’s Security Chief at the time).

There was a time when AV software was useful. We’re a decade past that, the world has changed, software has changed, defenses have changed, and AV software did not keep up.