Up until the end of the 17th season in 2021, the character Dr. Meredith Grey played by Ellen Pompeo has appeared in every episode of the show. This makes sense as she is not only the titular character of 'Grey's Anatomy' but also the main protagonist. The show revolves mainly around her life and career as a surgeon at Grey Sloan Memorial Hospital. Please do be aware that this could change in future seasons, and it would be a good idea to keep up to date on the news surrounding the cast and storyline of the show.