If you are looking for TeamSpeak 5, please check out com.teamspeak.TeamSpeak.
Add flathub:
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
Install:
flatpak install flathub com.teamspeak.TeamSpeak3
If you migrate from the original TeamSpeak (5) repository, just run the following to migrate your data:
cp -r .var/app/com.teamspeak.TeamSpeak/ .var/app/com.teamspeak.TeamSpeak3