Nighttime in Dying Light 2 is one of the most feared parts of the entire game. As soon as the sun sets, the zombies come out and flood the streets. With one false move, Aiden will alert every zombie on the map and they'll start barreling toward him until he gets to safety. Yet, somehow, this isn't the largest threat.
As the "Stay Human" tagline would suggest, Aiden needs immunity to stop himself from turning into one of the mindless creatures he fights. There are a few ways to prevent this from happening and no player will beat Dying Light 2 unless they have some way to build this immunity up.
Return To A Safe Zone
Learning to modify weapons can help with the nightmares outside. For the nightmare within, it's all about finding a safe zone for protection. If immunities get low and the times start to get into that yellow/orange/red territory, it's time to get home.
At night, these locations have UV lights that almost instantaneously get Aiden back to full immunity. They cost nothing, so this is the most efficient way of building up immunity. A word of warning; grey safe zones sometimes need to be unlocked first, which can take time. Stick to the green ones that have already been unlocked.
Find Inhibitors
Ideally, the best way to increase immunity is to not have to increase it at all. Eventually, players can get to a high enough level where they almost have to try and stay out for a long time. Doing so requires finding inhibitors, the main leveling mechanism in the game.
The game already has many fixes that it needs to undergo, so more inhibitors likely aren't coming anytime soon. These GRE Caches increase health and stamina, which is noticed quickly, but the natural boost to immunity is very much appreciated as well.
Take Immunity Boosters
Immunity Boosters come in different varieties, restoring anywhere between 35% and 80% of Aiden's immunity. Eventually, blueprints can be found so that Aiden doesn't have to find them, he can make them on his own. The good news here is that the materials aren't all that rare either.
As a special word of warning, it is possible but not advisable to increase immunity with UV Shroomz. The immunity with raw UV Shroomz only lasts for 35 seconds and they are an ingredient in the Immunity Booster, which ends up lasting far longer (especially when players have enough inhibitors).
Dying Light 2 was released on February 4th, 2022, and is available on Xbox Series X/S, Xbox One, PlayStation 4, PlayStation 5, Nintendo Switch, and PC.