https://www.techradar.com/news/youll-soon-be-able-to-make-skype-calls-from-your-alexa-device

Amazon has its own voice calling (and messaging) service built into Alexa devices (and the app), but if you wanted to use your Alexa-powered hardware to make Skype calls instead, this will be possible before long.

Microsoft has just announced that Skype calling is coming to Alexa devices, and will be rolling out “later this year”, so within the next few months. This will mean that you will be able to make and receive voice calls from your Echo, or indeed video calls if you have a device with a display (like the Echo Show).