This Variety article sums it up pretty well.
https://variety.com/2021/tv/news/cloris-leachman-dead-1234893925/
She was a multiple Emmy winner and an Oscar winner for
The Last Picture Show. One thing the Variety article does not mention is her turn as Billy Mumy's terrified mother in the
Twilight Zone episode,
It's a Good Life. She and Mumy reprised their roles in a newer (not the most recent) incarnation of the
Twilight Zone.
From the article, "The daffy, self-absorbed Phyllis, a character she claimed was close to her own persona, brought the actress two Emmys as a featured actress in a series during the mid-’70s and made Leachman a household name."