A small number of countries — the UK, Ireland, Finland, Malta and Norway — require dogs to be treated for the tapeworm Echinococcus multilocularis shortly before entry, because they're working to keep the parasite out entirely. Switzerland is not one of them: the parasite already occurs in the Swiss wildlife population, so there's no entry requirement to guard against it.
This matters most if your trip includes more than one country. Arriving in Switzerland first, then continuing on to the UK, Ireland, Finland, Malta or Norway? You'll need the tapeworm treatment before entering that second country, timed correctly — typically 24 to 120 hours before arrival there, not before you land in Switzerland.
If you're unsure whether your full itinerary touches one of the five countries that require it, it's worth mapping the whole route out with your vet before you leave, since the treatment has to be vet-administered and stamped, not just given informally.