Jean Grey Speaks: Sadie Sink on Making Her MCU Debut in ‘Spider-Man: Brand New Day’ and the Mutant’s Future With the New X-Men

For more than a year, Sadie Sink had to keep her role in “Spider-Man: Brand New Day” a secret. Sink, who was offered the part after her breakout performances in “Stranger Things” and “The Whale,” showed up to the London set without having read a full script. For security, her character was referred to with…