Microsoft has made the CDM extendable. This means that other interested parties can contribute their data definitions to the CDM. For example, the accelerator schemas have been created in consultation with industry and implementation partners.
Anyone can contribute to the CDM as it is open sourced in GitHub. For example, ISVs can, and are, adding their own data models to the CDM.
Adobe and SAP have joined with Microsoft in the Open Data Initiative, using the CDM to make the integration of data between applications and platforms far simpler in the future.
You can view the CDM in its GitHub repository at https://github.com/Microsoft/CDM.
One example of an implementation of the CDM is the Common Data Service.