Lived to the age of 95.

https://nypost.com/2022/10/04/joan-hotchkis-odd-couple-and-legacy-star-dead-at-95/

I remember Joan Hotchkis as Oscar's girlfriend in the first couple of seasons Dr. Nancy Cunningham. Then, like Chuck Cunningham on Happy Days years later, she disappeared without any explanation. If you have Paramount+, the episode where Oscar and Nancy meet can be streamed. May she rest in peace.