Its an exact duplicate of our site and its something that you should report so that action can be taken.
As per the official meta.seofficial meta.se post on the topic
The site is a proxy. Whatever the purpose of the site actually is, malicious or not, proxies represent a serious security threat to our site. Sometimes they even start showing up in Google results and users click on them not realizing that they aren't actually on Stack Overflow. Users get confused, or try to log in and accidentally send sensitive information to a third-party service.
And ... well, I double checked to make sure I was on the real site on other tabs, so clearly its confusing.
Please report it with the 'contact us' link, with relevant details like how you found the clone site so the community team (and maybe legal) can help handle the issue.