Genji is a great hero in Overwatch. He’s fast, can scale walls, boasts a great Ultimate for clearing grouped up enemies and features a precise projectile in the shuriken.
Genji also has the ability to deflect some incoming weaponry. This move is possibly best known for dealing with Bastions in turret form, but a simple press of the E key (or RB/R1 on consoles) can push some enemy projectiles bank onto their shooters.
It works for some things, but not all. It also works on Ultimates. Which Ultimates? Arekkz Gaming put together a video answering that exact question. Here it is.