With the latest hardware on both Laptops and Desktop computers, it might be necessary to install more recent hardware drivers, i.e. Linux kernels and xorg versions.
While it's possible to use backports from various sources on the internet, it's neither very safe nor tested very well. However, there is official support for the Hardware Enablement Stack in Ubuntu LTS-Versions, i.e. 16.04 and 18.04.
If your system is working fine without the HWE packages installed, it's best to just leave it alone. If you're sure issues on your system can be fixed by more recent drivers, e.g. for WiFi or graphics, here's how to install the the HWE stacks. Also, If your system has been installed with a point release such as Ubuntu 16.04.2, it may automatically come with the HWE stack installed.
Ubuntu 18.04 LTS
sudo apt-get install --install-recommends linux-generic-hwe-18.04 xserver-xorg-hwe-18.04
Ubuntu 16.04 LTS
sudo apt-get install --install-recommends linux-generic-hwe-16.04 xserver-xorg-hwe-16.04
Reboot
Since you just changed the kernel and graphics system, you'll want to reboot to apply those changes. If for some reason the new configuration does not work, you may at least select the previous kernel version during boot when grub asks.
