Hi Thomas,
Welcome to Microsoft Community.
I'm Hahn and I'm here to help you with your concern.
As of now, Surface Pro 10 for Business does not support LTE/5G connectivity. There is also no clear news on when the Surface Pro 10 for Business 5G version will be launched.
If you're looking for a Surface device with LTE/5G capabilities, see: Insert a SIM card into your Surface - Microsoft Support
They offer LTE/5G connectivity and could be suitable alternatives if this is a crucial feature for you.
Your Sincerely
Hahn. W - MSFT | Microsoft Community Support Specialist