Reference Teams client support
Since launch Teams has supported IE, Edge, Chrome and Firefox. Mac users had to use the full client or a third party browser and iPad users had to install the client. There is a user voice asking for native Safari
Reference User Voice
Now Microsoft have confirmed in a recent Education blog post that Safari support is coming. No details of it being full audio video support or just chat, channels and teams, we shall see.
Nothing on the official roadmap yet, so no ETA.