MacBook Pro Keyboard and Mouse Stopped Working

The integrated keyboard and trackpad on my usually 100% reliable late 2015 MacBookPro stopped working suddenly. The MacBook still functions perfectly with an extended USB cable keyboard and a magic mouse.
I have not deliberately made any settings changes and cannot find anything that explains the sudden loss of function.
Can anyone suggest a solution?

My main computer is a late 2020 iMac, and only the MacBook when I travelled a lot. I now travel very little, but visited South Africa for a month shortly after the MacBook problem developed. This forced me to use my iPad for “serious” work, and not just reading and watching videos. I needed to make many changes to my iPad set-up and my way of using it, but achieved everything I needed with it while away from home. I will try to write a not about it.

That’s probably a hardware break, unfortunately. I would have it looked at. Hopefully it’s just a problem with the keyboard or trackpad hardware and not the logic board. They’ll do software tests and resets, too, to rule that out.

Thank you cornchip.
The problem persists. Now the seasonal festivities are over I will arrange a check. The upside is that it forced me to use my iPad when travelling, which in turn made me change the set up and the way I used it. Since then I have had greatly improved value out of my iPad for serious work rather than watching videos and reading.
Happy New Year.