In this year's Disney Plus Day event, Marvel announced that Echo will be getting a spin-off series, with Alaqua Cox reprising her role for the show. This implies that Echo could play a significant role in "Hawkeye."
It would also be ground-breaking for Marvel as the first live-action series led solely by a deaf and Native American actress following Lauren Ridloff's introduction in "Eternals" as the MCU's first deaf superhero.
If the series does follow "Hawkeye," we could see Echo's journey from a villain to a hero, a bit like "Loki," so she can join other heroes later in the MCU story. The "Hawkeye" series so far has focused a lot on Hawkeye's Ronin outfit, which could mean that Echo will take on the mantle like the comics and use it to become a hero and an Avenger.
Alternatively, she may cross over with another character scheduled to make an appearance in "Hawkeye," Yelena (Florence Pugh). It is established in a "Black Widow" post-credit scene that Yelena thinks Hawkeye killed her sister, which would give reason for Echo and Yelena to team-up as enemies of the Avenger in "Hawkeye." Pugh won over fans with her performance in "Black Widow" but has not been announced to appear in the MCU beyond "Hawkeye" yet.