All signs point to Andretti/GM joining the grid as 11th team in 2026. They are also committed to building their own power unit by 2028.
https://www.bbc.com/sport/formula1/articles/c3vly6rlxe9o
https://racingnews365.com/exclusive-f1-set-to-welcome-new-team
https://apnews.com/article/f1-andretti-expansion-towriss-1de51966929f09616110d2ae9b5e1d79
Hopefully they get to keep the Andretti name, but overall 11th team on the grid is definitely a win.
With so much talent on the grid and stuck on the sidelines more seats would be a great thing for almost everyone.