The Survivor Pass is a Battle Pass in BATTLEGROUNDS.
What is the Survivor Pass? Previously called the Event Pass, Survivor Pass is a form of progression in BATTLEGROUNDS. By completing in-game missions and earning levels, you will be able to unlock rewards (these rewards are ranged between changing your in-game username to cosmetic items that aren't tradable or marketable). The pass is a new way, without limiting it to DLC. The Event Pass is designed to reflect the opinions of players who wanted a trackable progression-related system, and at the same time allows you to unlock new content in PUBG in a way that is different from the crate and key system.
Just like the crate and key system, you’ll be able to get rewards in the Survivor Pass system regardless of whether you made a purchase. If you haven’t paid for the pass, you can temporarily unlock many of the items (and earn one special item permanently). However, you can also permanently unlock a ton of exclusive reward items by paying to unlock the pass and completing certain missions to “level up” your pass. If you’re hesitant about buying the Pass, but want to play the missions, you’re free to do that. And your mission progress is always tracked, so you can buy the Survivor Pass late in the event and still get all the rewards you’ve earned.