https://www.gamesradar.com/left-4-dead-2-the-last-stand-dlc-launch/
The Last Stand adds more than 20 new survival arenas, four new scavenge arenas, and a campaign mode on The Lighthouse map. There’s 30 new achievements, new melee weapons, new and reworked character animations, and previously unused lines of dialogue (I’m personally a fan of “Oh, it’s a xxxx apocalypse now, xxxx!” The update is free for all PC players, and again, it’s the first major DLC since 2012.