The date has been set for the Chang fork event when CIP-1694 will kick in. At this point Cardano will become arguably the most decentralised block chain on the planet as on-chain governance passes to the community via dReps and Intersect, the members based organisation. dReps will perform a similar role to elected representatives in a democracy.
This is the last phase of the original Cardano Roadmap, and while there are elements of Basho (Scaling) and Voltaire (Governance) which will still require further development this represents a monumental milestone for the project overall. It has come a long way from the original whiteboard session.
June is going to be an exciting month!