The character of Jesse Quick (played by Violett Beane) first appeared in the second season of The Flash and went on to recur in subsequent seasons.
Hailing from Earth-2, she is the daughter of Dr. Harrison ‘Harry’ Wells (Tom Cavanagh), an ally of Team Flash. When Jesse was first introduced, she was a prisoner of the villainous speedster Zoom.
Later becoming a speedster herself and forming a relationship with Wally West (that later ended), Jesse appeared less frequently after her actress, Violett Beane, was cast as the female lead on the CBS dramedy God Friended Me.
Beane played journalist Cara Bloom for two seasons before God Friended Me was cancelled in April 2020. During the run, Jesse Quick appeared to meet her end in the Crisis on Infinite Earths crossover when Earth 2 was destroyed.
As The Flash has shown on multiple occasions, there are many ways to bring back a dead character in this superhero universe. Michelle Harrison (Nora Allen), John Wesley Shipp (Jay Garrick), Rick Cosnett (Eddie Thawne) and Wentworth Miller (Leonard Snart) are some examples of actors returning after their characters were killed off.
Perhaps Jesse could have protected herself in the Speed Force? Or Beane could return as a new character, a doppelganger of Jesse. Whichever the method, on The Flash, is outside the realm of possibility.
The Flash airs Tuesdays on The CW.