If you mean Dual SIM with to physical SIM cards, then no, this is not available for iPhones in Switzerland. However, if you buy an unlocked phone (i.e. not locked to a provider), you should be able to insert one physical SIM card and use another subscription via eSIM. I believe all three major cell phone providers in Swizterland (Swisscom, Sunrise and Salt) offer eSIMs, but availability of eSIMs from other providers or for pre-paid subscriptions is probably restricted.

Disclaimer: I have not actually tried this.