Keyboard shortcut to navigate/cycle between visible windows on screen

Question

I have two windows(e.g a document and a browser). I have maximized them such that the document completely occupies the left half and the browser completely occupies the right half of the screen ( I do this easily with the keyboard shortcuts of Spectacle)

What is the keyboard shortcut to navigate quickly between these two visible windows?

Cmd + Tab is not ideal because if I use multiple virtual desktops(like workspaces in Linux) and I go to a third application there in another desktop, when I come back to the virtual desktop which contains my browser and document, Cmd + Tab brings in the third application to the mix.

Cmd+Space and then typing the application name(e.g the browser application or the document application) is the closest I could get to what I originally wanted.

Is there a software or configuration that I can use to get this functionality?

Answer 1

Those would be

Control+F4 - Move focus to the active (or next) window

Shift+Control+F4 - Move focus to the previously active window

If you have the "F keys as standard function keys" option disabled in System Preferences > Keyboard, enable it.

Or use Fn in addition to the above shortcuts.