I need an implementation that allows me to connect two clients, one in react Js and the other in react native with expo-cli, through a video call, but I don't know if is possible to do that in these conditions. I'd like some example or alternative to solve that.
You have to use something called WebRTC , it allows you to stream audio and/or video media.
For browser , Read This article
For react native, your going to need a package called react-native-webrtc , Read more in This page.
Also read This