InterSystems IRIS is a new product that incorporates and extends the capabilities of Cache, Ensemble, DeepSee, and iKnow, with a significant set of new capabilities. See https://community.intersystems.com/post/intersystems-iris-data-platform for more information.
Existing applications that were developed using Cache and Ensemble can be upgraded to run on InterSystems IRIS, usually with little or no modifications. However, it is not required that customers migrate to InterSystems IRIS. We continue to support Cache and Ensemble and have no plans to discontinue support for these products. However, we suggest reviewing the new capabilities available in InterSystems IRIS, and consider migrating if there is an opportunity for your applications to take advantage of the new functionality.
Regarding your second question, both HealthShare and InterSystems IRIS are being increasingly adopted by the commercial and government payer community to create unified health records for the better management of care and business processes.