ApexDBR discovered references to both survival and team deathmatch modes in Apex Legends' files. At the moment, the game only contains a squad mode and single—albeit massive—map.
RealApexLeaks did a bit more digging and uncovered additional details shared with GamingIntel. According to the files, the survival mode will feature an NPC crowd that reacts to players by cheering them on, giving standing ovations and booing. Commentary will accompany the matches, too, judging the performance of the survivors. I find the game stressful enough without an audience, honestly, so I think a few boos and jeers would finally break me.
A list of names also appears, apparently not playable characters. They're references to host NPCs, but it's not clear what impact choosing one will have on the match. It looks like kill replays will play during survival mode, too, letting you relive your murder.
What players will actually have to do during the mode is still a mystery, although at one point it may involve dealing with a hover tank. Respawn isn't talking about new modes yet, even in the roadmap. Judging by how Apex Legends launched, however, stealth launching new features or modes seems plausible.
Respawn confirmed new Legends are coming, and some references to them may have been dug up. The rumoured Legends are Octane and Wattson, while Tesla trap and stim could refer to their abilities. Not that any of this matters to me, a person who only plays Gibraltar for some reason.