Kubernetes requires a tool which implements the Container Runtime Interface (CRI), a standardized API for starting & managing containers. This is from 2015-2016[1]. The CRI interface is defined by & owned by Kubernetes, and there's a lot of implementations: runc, crun, youki, dockershim and likely more.
For a while Kubernetes has included something called the "dockershim", it's own implementation of a CRI interface that, under the hood, calls Docker or Podman, so Kubernetes "pods" run in Docker/Podman. There's also tools like Kind[3] ("kubernetes in docker") that go further- not just hosting Kubernetes worker containers in Docker, but hosting the main kubernetes daemons also in Docker.
Kubernetes deprecated Dockershim, formally in December 2020, but is just throwing the switch now in the upcoming 1.24, expected mid-April[4]. A company Mirantis has pledged to take over support of Dockershim[5], and is calling the new effort "cri-dockerd"[6]. This should allow Kubernetes workers to continue to run via Docker or Podman.
Kind is unaffected, since it runs the main Kubernetes controllers in Docker, which then launch their own opencontainerd (one off the main CRI implementations) inside that Docker container, nested like, so no dockership/cri-dockerd is needed).
Worth re-noting that Podman includes tools to try to run Kubernetes pods directly, without running the rest of Kubernetes.
