A bug with the Trauma Kit allows players to drop into the Blackout map with 200HP, 50 more than the standard, and is ridiculously easy to do.
Although it will likely be fixed soon, as Treyarch has been keeping a keen eye on various gameplay issues and bugs since release, it is still nuisance for now.
It is far from game breaking, as you Trauma Kits, while rare, are often found upon landing, but with this bug you will almost certainly enter your first engagement with the advantage.
By simply finding a Trauma Kit in the staging area, and using it immediately, you will find that when you jump out of the helicopter, you retain the extra 50 health points granted by the Trauma Kit.
Streamer emmkim managed to perform the bug, and may not have even noticed he had done so, but if you look at his health bar in the bottom left, you will see he has kept the Trauma Kit's benefit.
It's unclear if you must time the use of the Trauma Kit with the loading of the game, as emmkim does, or if it can be done at any point during the 30 seconds typically spent in the staging area.
There is also another, more common, bug with the Trauma Kit, where it will simply have no effect at all when used mid game.
As aforementioned, Treyarch have been keeping a keen eye on all the bugs and gameplay problems across multiplayer, Zombies and Blackout in Black Ops 4, so expect these Trauma Kit issues to be fixed soon.