There is no LAN support that I know of, but as long as both of you are online, play an online game but make a private match of you don't want anyone to join. It would be the same thing for y'all as it would be playing local together anyway.
Local means you both play on one computer (one will use a game controller). If you want to use two pc's, connect online, then use open, not ranked. Host a game and let the other computer connect. If for some reason the other pc can't connect, use hamachi. There are plenty of guides out there how hamachi works and its very simple, google it.