There's still no word on when What If...? season 2 will premiere on Disney+, but the first merchandise for the show (first revealed on Toonado.com) appears to reveal Captain Carter's updated costume.
Peggy Carter is now wearing a tunic/dress that's not too dissimilar to what Betsy Braddock has donned in recent comic books. She's also wearing armour on her shoulders and can be seen in a red cloak as well. This is a pretty significant redesign, though there may well be a good reason for that.
Captain Carter appeared in Doctor Strange in the Multiverse of Madness, leaving many fans under the assumption that the Earth-838 Peggy and What If...?'s Variant were, in fact, one and the same. That's not the case (a relief given what happened to Cap at the hands of the Scarlet Witch), but something needs to be done to better differentiate the two, and this works.
Captain Carter is expected to be a focal point on What If...? season 2 in an episode that puts a new spin on Captain America: The Winter Soldier. During last year's San Diego Comic-Con, the hero was shown alongside Steve Rogers and Black Widow as robots closed in on them, so we'll see how that adventure plays out.
We've also heard rumblings that her relationship with The Watcher will continue to deepen, hopefully meaning Hayley Atwell is given the chance to shine in Avengers: The Kang Dynasty and/or Avengers: Secret Wars.
What If...? season 2 is expected to return to Disney+ later this year, though there have been rumblings about it being pushed into 2024.
Stay tuned for updates.