Lenovo Thinkpad E480 - Bluetooth not working in Ubuntu 18.04
Ubuntu does not have pre-installed drivers for Realtek Hardware. You were lucky that your wifi worked fine, because I had suffered about almost a month repairing the wifi issues. Now let's solve the realtek problem:
First ensure that you are having Linux kernel > 4.14. To check that, type following on terminal:
uname -msr
If you get something like Linux 4.15, assume everything is fine. And just in case if its not higher than 4.14 (since you are using Ubuntu 18.04, by default the Linux kernel which comes in package is 4.15, so this is for the ones who are still at Ubuntu 16.04), Connect to Ethernet and type following commands:
sudo -s
sudo apt-get dist-upgrade
sudo apt-get upgrade
sudo apt-get update
reboot
This will take time, but have patience. By now you should have linux kernel > 4.14. Now comes the real driver installation part.
Ensure you have installed git. If not type the following command:
sudo apt-get install git
git clone https://github.com/tomaspinho/rtl8821ce.git
cd rtl8821ce/
sudo make all
sudo make install
sudo modprobe -a 8821ce
reboot
This should solve your problem.