For example, there's Tracer that dual wields handguns, is pretty quick on her feet, and can rewind time when in a tough spot, which makes her well suited to hit-and-run tactics. Each character has its own strengths, weaknesses, and unique playstyle.
You'll still be shooting and bashing your way to victory, but instead of picking different weapons, you'll be often switching between one of the many characters. Unique FPS gameplay Overwatch combines traditional team-based FPS elements and MOBA-esqe characters with unique abilities and weapons.