One of the most intriguing aspects of Marvel Studios' What If...? TV series is how fluid and dynamic it can be in terms of the narrative. Some episodes pick up on old storylines, such as Captain Carter battling the Hydra Stomper. While other Season 2 stories bring new adventures to light, like a young Peter Quill fighting the Avengers.
Source:https://www.cbr.com/what-if-happy-hogan-saved-christmas-biggest-referrences/