Starting in 2025, all Part D and Medicare Advantage plans will have a $2,000 annual cap on out-of-pocket prescription drug costs (this cap was previously $8,000). Once you hit this threshold, your costs for covered prescriptions will be $0 for the rest of the year.
https://www.ncoa.org/article/what-you-will-pay-in-out-of-pocket-medicare-costs-in-2025/