Generally when you open a new tab and pop open the Network panel in the chrome devtools, you won't immediately see any traffic. This is because the initial network requests to load the site happened before you accessed the Network panel.
If you'd like to view the Network traffic immediately without having to refresh the new tab, you'll have to make the devtools panel open automatically with new tabs.
- Click the triple dot icon from the top of the devtools panel
- Click 'Settings'
- Find the 'DevTools' section
- Check the box for 'Auto-open DevTools for popups'
Now, whenever you open a new tab, Chrome devtools will be open and the initial network traffic will be recorded.