There seems to be a problem with the kernel on 19.04.
After upgrading from Ubuntu 18.10 to 19.04 on my Lenovo Thinkpad L580 and lost both Trackpoint and the Touchpad. Only external mice worked.
Checking xinput shows that its not even there:
Some guy had similar problems and ran this command to get the elantech driver working again:
sudo sh -c 'echo -n "elantech"> /sys/bus/serio/devices/serio1/protocol'
And now its working again!
From what I understand they have problems with the elantech driver that seems to have creeped up newer kernels. Haven’t found a solution that survives reboot.