We just released CEP 8.0 last week, which updates to CEF 57 and Node.js 7.4.4.
More info on CEP here: https://www.adobe.io/apis/creativecloud/cep.html
And we have a GitHub org with libraries and samples here:
The actual app is a standard web app based on React that connects to a GraphQL server.
Edit: fix typo
CEP is for building extensions with HTML+JS+CSS. ExtendScript (an old JS dialect plus Adobe extensions) is for internal product scripting (e.g., building/manipulating the document model in InDesign).
You can bridge the two, of course, but there's no direct connection or even relation without explicit developer effort.