The two MIT-like schools in Switzerland, EPFL Lausanne and ETH Zürich are big tech hubs.
Also Google has a huge hub in Zürich, and most of the other big tech companies have offices there or in Zug. And as someone mentioned, there’s a lot of crypto-stuff going on in Zug.
Oh and before I forget, Bern has a bunch of OpenData/government IT stuff going on, and Basel is a hub for medical companies (Novartis and friends), and thus has a lot of med-tech companies.
Also Google has a huge hub in Zürich, and most of the other big tech companies have offices there or in Zug. And as someone mentioned, there’s a lot of crypto-stuff going on in Zug.