Stop Cisco AnyConnect Secure Mobility Client from starting up automatically
Removing the following worked for me.


/Library/LaunchAgents/com.cisco.anyconnect.vpnagent.plist
/Library/LaunchDaemons/com.cisco.anyconnect.gui.plist


Update:
For macOS Catalina and anyconnect 4.7.x removing this single file seems to be enough:


/Library/LaunchAgents/com.cisco.anyconnect.gui.plist