Whatever your citizenship is, you need to apply for a Swiss residence permit to live in Switzerland.
If you or your partner (married) have an EU or EFTA passport the application for a Swiss residence permit has become more easily because of the bilateral agreements between Switzerland and the EU.
For all other nationalities, the application requires more conditions to be fulfilled and can be more difficult, but there are solutions.
You are a writer, painter, music star, sports star or another exceptional individual.
You don’t have any economic activity in Switzerland and wish to settle down in the country
and benefit from a lump-sum taxation.
If you fulfill certain conditions you can benefit from a lump-sum taxation, where your taxable income is limited and based on your cost of living in the country. This means that you only pay a fixed amount of taxes independent form your real income and fortune.
You don’t have any economic activity anymore and wish to retire in Switzerland.