Inquiry About Games I Could Play With My Brother While We're at University

So my younger brother and I both share an interest in gaming. However, I've been away at school for the past couple years, and he'll be heading off soon as well so our chances to bond and enjoy eachother's company have become pretty sporadic. Basically, we're looking for suggestions for one or a few multiplayer games we could play together (shooters, card games, strategy, fighting, RPG, whatever) to sort of reconnect. The only criteria we have is that ideally the game would have some considerable depth to it (i.e. not something casual and arcadey like Gang Beasts or Fun Run, but something more complex like Age of Empires or Hearthstone). Thanks in advance.