A friend of mine pointed that at the end of the trailer, it appears that Cayde is being carried by the Eco Stranger. It may be a bit of a stretch, considering we can't see their face, but the cloak looks pretty similar to the one the Exo Stranger is wearing on the grimoire card from D1.
Exo Stranger carrying Cayde (???):
https://imgur.com/a/ghocYi9
Exo Stranger Grimoire Card:
https://imgur.com/a/WCBtdyN
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Matches the Strangers cloak in D1, im willing to bet it is her. Given caydes connections to braytech. And all the lore surfacing about her it would be cruel for it to be a coincidence of appearance.