As you may know, Skype is a popular instant messaging and video conference application, acquired a few years ago by Microsoft.
The latest stable version avaible is Skype 8.34.0, which comes with a bunch of changes.
In order to successfully install the latest version of Skype available on Ubuntu 18.10 Cosmic Cuttlefish, Ubuntu 18.04 Bionic Beaver, Linux Mint, Elementary OS and other Ubuntu derivative systems, you need to install the snapd package (and install the skype package via the snaps):
$ sudo apt-get install snapd
$ sudo snap install skype --classic
To remove skype, do:
$ sudo apt-get remove skype