Epic Games reintroduction of the 50v50 mode was, without a doubt, a roaring success. Fortnite 50v50 mode allowed players to do things that they simply weren't able to do even with a four-man squad, this larger squad mode let them feel more like a unit as they fought against hordes of the opposite team in what could only be called a battle rather than a simple firefight.
Of course, Epic Games aren't blind to the overwhelming love for the mode, even stating in their blog post that they've "heard you about your love for 50v50 and [they are] currently evaluating keeping a larger squad mode live at all times for those who enjoy that type of battling more!"
This no doubt is enough to excite any fan of the 50v50 mode, however, the developers did not give any further indication about any additional details about the mode, nor when said mode may be available in the future. Nonetheless, the fact 50v50 mode was brought back in the first place is pretty important, especially when you consider it's the only mode that's been brought back for a second time.
Epic Games first revealed the 50v50 mode back in December, during the 2017 Game Awards. Though at the time it was simply known as the 'Last Team Standing' mode. It's inclusion, even back then, pleased many fans and no doubt helped propel Epic Games' successful Battle Royale to its current position as a game that's celebrated even by celebrities like Drake.
Unfortunately, there is no telling whether Epic Games will be including any other larger squad modes in the future, but if they do at least the development team will know that their player base hold squad modes in good favor and thus will act accordingly to make Fortnite bigger and better than ever.