Several Avengers stars have died, with notable mentions including Chadwick Boseman, who played Black Panther and passed away in 2020 due to colon cancer. His death was widely mourned, and Marvel chose not to recast his character, instead honoring him in subsequent films. Another notable mention is Jeremy Renner (Hawkeye), who survived a severe snowplough accident where his heart stopped temporarily but did not die permanently. Several other MCU actors have also passed away but were not necessarily Avengers stars. Here are some key points:

• Chadwick Boseman (Black Panther) died in 2020 from colon cancer and was honored by Marvel without recasting his character.

• Jeremy Renner (Hawkeye) had a near-death experience in 2023 but survived.

No confirmed permanent death of an Avengers star (actor) occurred aside from Chadwick Boseman as of now. If the question was about the characters in the Avengers films who died, that includes fictional character deaths like Tony Stark (Iron Man) but this answer focuses on actors themselves who were Avengers stars. Let me know if a focus on character deaths is desired as well.