Since its genesis, Kubernetes has been the go-to container orchestration solution for enterprises needing scalable containerized applications implemented on microservices architecture. It essentially deals with the Pod as the most basic unit, which may hold one or more containers. Since any application deployed within Kubernetes is executed through one or more Pods, it is important for the user to ensure that they are secure from misconfigurations and security breaches. Thus, Pod security is not just a major concern but a necessity for Kubernetes clusters and even more for business-critical applications.
To fulfill this need, Kubernetes introduced PodSecurityPolicy in its v1.3 release. However, PodSecurityPolicy has been officially deprecated by Kubernetes in the v1.21 release and has been entirely removed in the v1.25 release, which was a step taken due to some major issues encountered by users throughout the years of its use that could not be addressed without introducing breaking changes (more details could be found on an official post made by Kubernetes).