CDs are Constitutional Conservers that operate Protocol Delegation System smart contracts, and receive various benefits while being subject to specific requirements in addition to the Constitutional Conserver requirements. They vote for strategies that are in alignment with the Constitution.
Although Governance Strategies are created by CVCs, there is a need for a consensus on said strategies. Constitutional Delegates employ these strategies and vote in alignment with the constitution. The interaction between CVCs and CDs act as a checks and balances system to ensure that ideologies are in alignment with the constitution. Read more about it in Endgame 101.