On my Intel NUC, I was trying to install the intel drivers in order to make sure that the hdmi is fully operational.
So I installed xserver-xorg-video-intel which was supposed to install all the video related packages including the relevant drivers for HDMI support.
Unfortunately, after doing this, the keyboard and the mouse stopped working. No clue what the hell is happening.
Seems that there is a dependency issue in the package since many xserver-xorg-* packages have been removed.
Ubuntu installed on my system is 16.04.5 LTS.