I have recently installed Ubuntu 20.04 on my Toshiba Satellite L50-A-18T laptop and everything went smoothly except when I noticed that neither the keyboard nor the track pad worked, only external keyboards and mouses. I have tried to look for a solution but no luck. This only happens when I boot into Ubuntu, if I boot into windows the keyboard and track pad work fine.
Using a chuwi aerobook, had the same problem, tried most of the available solutions online and patches to no effect. I then reinstalled 20.4 to find keyboard stopped working again after half day.
As it turns out, after recovery mode boot, keyboard / track-pad work again, although lost control of screen brightness. :)
Waiting for a more 'permanent' solution.
I had the same problem and tried reinstalling the drivers and updating kernel but didn't help. So I went to the BIOS configuration and checked if the mouse pointer worked there. Initially I couldn't see the cursor in the BIOS menu but I tried to enable the mouse pointer by pressing
Fn + F5 (might be different in your case) and the mouse cursor started to appear and worked in the BIOS menu. I simply restarted my system after that and logged into Ubuntu and the touchpad worked.