The context is optional. But without context, copilot has nothing to work on. So the correct answer should be:

„Are you stupid?! Which numbers are you talking about?“ instead of „sure thing, the sum of nothing is clearly 15!“

There absolutely is a =Copilot() function, but only available in the beta version of Excel. It is also officially documented: https://support.microsoft.com/en-us/office/copilot-function-5849821b-755d-4030-a38b-9e20be0cbf62