It had been thought that Respawn had been working on a followup to Titanfall 2, and perhaps it had been at some point. However, Eurogamer asked Respawn Producer Drew McCoy if there were plans for a third official sequel in the works. His answer was a definitive no.
“There are some people who think there are too many battle royale games or it's a fad, the world thinks we’re making Titanfall 3 and we’re not — this [Apex Legends] is what we’re making,” McCoy said. “To try and convince a skeptical audience for months with trailers and hands-on articles, we’re just like, ‘Let the game speak for itself’ — it’s the most powerful antidote to potential problems. We’re doing a free to play game, with essentially loot boxes, after we were bought by EA, and it’s not Titanfall 3. It’s the perfect recipe for a marketing plan to go awry, so why have that - let’s just ship the game and let players play.”
"We're doing a free to play game, with essentially loot boxes, after we were bought by EA, and it's not Titanfall 3."
After the release of Titanfall 2 in the fall of 2017, the studio had indicated that it was beginning work on the next game in the series. Electronic Arts acquired Respawn on December 1, of that same year. From McCoy’s statement, it almost sounds as if EA had considerable influence on the direction that the new entry would take, perhaps even changing the plans entirely.
McCoy did not elaborate any further on the subject. So whether EA had anything to do with drastically changing T3 into Apex Legends is pure speculation. Perhaps a battle-royale game was what they had planned along. However, it does fit EA’s recent tendency to take popular franchises and cash in on their name using microtransactions.
As for fans that were hoping for a third chapter in the Titanfall series, there is still hope that Respawn can revive it sometime in the future, but don’t expect it any time soon.