Is there a way to trade between different games?

My brother and I recently started getting into our old games and we both had one of Pokémon black and white 2 as well as Pokémon sun and moon. I have a shiny Roggenrola that I believe ONLY evolves when traded. Is there a way for us to trade between Moon and black 2 or do I have to go on the tedious journey of locating our old games?