All you need is the "Camouflage-Grease". You can get the blueprint by playing the DLC 1 (Bloody Ties), to which all players should have access now. I'll tell you, what you have to do.

Then you should read my other guide first:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3120803030

Playing the DLC you'll meet Astrid. Work with her together against Skullface. During the game she'll ask you, to investigate the room from Skullface. This starts the sidequest "The Gilded Cage".

After doing the sidequest Astrid will meet you later in the arena and give you the BP for the grease. Maxed out, it will protect you for 60 seconds. To craft one you need 1 honey and 3 rare trophies.

Hidden by the "Camouflage-Grease" you can sneak around, climb, loot, lockpick doors and chests. You can even use your flashlight. Comming the infected to close or making to much noise, will call their attention, but as they can't see you, they won't attack you. So you can investigate danger zones and buildings like GRE-Genomics-Center even in the daytime.

But always be aware: as soon as you attack any infected the grease will loose its effect - and you're done within seconds

This might also be heplful:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3041534840

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3169463013

Good night, good luck......




















.... and stay human