I figured out who the person in the The Marvels trailer is : r/marvelstudios

The Marvels Trailer Finally Reveals New Marvel Movie Villain

In new ''The Marvels'' trailer briefly highlights the 'X' in a 'What Comes Next' header. Do you think it connects to the X-Men? : r/marvelstudios

New The Marvels leaked stills from the second upcoming trailer, which is rumoured to be released in roughly 15 hours (July 20th, Midnight PST) : r/ marvelstudios

Report: The Marvels - First Trailer April 11th! : r/marvelstudios

Brie Larson was announced as our Captain Marvel exactly 7 years ago! : r/ marvelstudios

Marvel Studios - Phase 4 : r/marvelstudios

Who is the Villain in The Marvels? Zawe Ashton's Marvel Character Explained

Final Marvels trailer wants you to think The Avengers will show up

The Marvels' Trailer: Brie Larson's Captain Marvel Battles Vengeful Villain – The Hollywood Reporter

Marvel Studios' What If…? Season 2, Official Trailer

Predictions for The Marvels post release dialogue. : r/MCUTheories

New character posters from The Marvels! : r/marvelstudios

Missing Sequences in 'The Marvels'? : r/marvelstudios