CDM (Conceptual Data Model) : This Data Model defines WHAT the system contains. This model is typically created by Business stakeholders and Data Architects. The purpose is to organize, scope and define business concepts and rules.

PDM(Physical Data Model) : This Data Model describes HOW the system will be implemented using a specific DBMS system. This model is typically created by DBA and developers. The purpose is actual implementation of the database.

 

Source : https://www.guru99.com/data-modelling-conceptual-logical.html