If you are Swiss resident, you are taxed in your canton of residence.
If you are not Swiss resident, you are taxed in your country of residence and subject to withholding tax levied by the canton where the pension fund is domiciled.
The country of residence can be quite high esp. if they treat the withdrawal as subject to normal income tax. There are horror stories of people who didn’t plan losing 40% of their pension pot in their new country.
Contrariwise, you can get your pension tax-free if you withdraw it in a country that doesn’t tax the pension locally but also has a double-tax treaty with Switzerland which enables you to reclaim the withholding tax paid.