This has been evidenced by how both WandaVision and Loki will tie into Doctor Strange in the Multiverse of Madness, and how characters like Ms. Marvel and She-Hulk will eventually show up on the big screen once they’ve been introduced on the small screen.
Marvel Studios president Kevin Feige has also said these shows will be just as integral to the future of this franchise as the movies.
So now, in addition the cinematic side of the MCU continuing into Phase 4 and beyond, we also have these Disney+ shows on Marvel that will spotlight characters who weren’t likely to star in their own movies.