Kubernetes is a container orchestration tool. With an increase in the use of containers, the need to manage containers increased. Kubernetes is one of the best tools for this purpose.
Kubernetes is used by most of the companies to deploy their product and moderate external traffic. Pokémon Go is one of the best examples. Pokémon Go wasn't ready for such huge traffic but since their deployments were on a kubernetes platform which provided functionality to upscale as in when required, it survived without crashing.
Have a look at this to know more about Kubernetes case studies.
Have a look at these blogs to get a better understanding of what is Kubernetes, why use Kubernetes with demos.
Hope that helps