Site Isolation has been enabled by default in Chrome 67 on Windows, Mac, Linux, and Chrome OS to help to mitigate attacks that are able to read otherwise inaccessible data within a process, such as speculative side-channel attack techniques like Spectre/Meltdown. Site Isolation reduces the amount of valuable cross-site information in a web page’s process and thus helps limit what an attacker could access.
Type this in your Chrome address bar to enable this feature:
Then select the Enabled to use it.
You can read more about this feature here.