Palo Alto is a major player, absolutely. So are Cisco and MSFT. For pure cybersecurity plays, pretty much any of the top 5-10 companies held in the ETFs BUG or HACK are prominent players in the cybersecurity space. I used to own BUG but sold out last month as part of some portfolio rejiggering. (IIRC BUG holds Varonis, but I'm not familiar w/them specifically).