Double jumps/Sprinting/Side Dash/ADS honestly this is not a HALO game and that is coming from someone who has never been a HALO fan. I do however know what HALO is and this isn't it. That is not to say the game looks bad at all because it does not it looks very fun but it seems to be catering to a completely different audience than past HALO games. This could be a good thing or a bad thing depending on where you stand.
There are no double jumps in Halo 5. You can only boost forward, backwards, and side-to-side. You can also utilize a hover ability while descending in the air.