Link looks noticeably different in the new trailer for The Legend of Zelda: Breath of the Wild 2. There are certain shots throughout the trailer where Link is sporting a green tunic and long-flowing hair, made more dramatic by switching to shots of the prim and proper Link from the first game. While the trailer seems to insinuate that this is due to the passage of time after escaping Ganondorf's cave, the reality may be that this isn't Link at all - at least not the Link from the first Breath of the Wild.
This wouldn't be the first time a Zelda game featured two different Links in one game. In Twilight Princess, there are various points where Link enters a different realm to train with a figure called the Hero's Shade, who teaches him skills like the finishing blow which is used to defeat Ganondorf at the end of the game. What makes the Hero's Shade in The Legend of Zelda special is that he's actually the undead spirit of Link from Ocarina of Time, using his spirit energy to communicate with his descendant and give him the skills he needs to succeed.
This is likely the case with this new Link, with the exception that he will be a playable character in BOTW 2. His character design is too different, and Nintendo made a point to not show his face at any point in the trailer, suggesting that this Link looks different from what fans are used to. Given his hair, clothing, and even his arm, this new Link is likely the Ancient Hero from Impa's tapestry.
Why The Link In BOTW 2's Trailer Is The Ancient Hero
In examining the Ancient Hero's depiction, the design choices that are of particular interest to this theory are his hair, clothing, and hand. The hair is a bit tricky considering the tapestry depicts long red hair, not blonde. This small detail has led to a variety of theories such as this figure actually being Ganondorf instead of Link and the red hair being a depiction of the Zonai helmet. The reality is that it's likely an artistic choice to differentiate this figure from Zelda, which is supported by the choice to color the activated Sheika Towers red instead of blue. So aside from the red coloration of the hair, the length and free-flowing nature of the Ancient Hero's hair is identical to this new Link's.
The iconic green tunic is another similarity between the two, with this new Link sporting a tunic that looks more like Skyward Sword than BOTW. Finally, the yellow right hand from the tapestry never drew much attention but now, with the altered right arm, it may suggest that the Ancient Hero had the same augmentation. The main counter-argument to this would be that the altered arm is green, however there are two pieces of evidence that support this theory: firstly, the different color may be another artistic choice to standout against the green tunic and, secondly, when Link uses his arm to send a spiky ball back towards enemies via a potential time travel ability in BOTW 2's trailer, the hand glows yellow. Perhaps the Ancient Hero is activating the arm's power in the moment the tapestry is depicting.
Character design is a central part of Nintendo's identity, having created a variety of iconic characters that are instantly recognizable. With that in mind, it doesn't seem like a coincidence that the design of this new Link is so similar to the that of the Ancient Hero, especially since the series has established the importance of time travel and lineage in the world of Hyrule. While no one will know the truth until the release of Breath of the Wild 2, or the reveal of the now withheld official name, the differences in character design hint towards the presence of a new hero.