A duplicate case is an open instance of your case type that matches a set of conditions.
For example, you can find Order Shipment cases that have the same shipping address as your current case to avoid duplicated bills or charges. You can also use duplicate case tracking to report on information in cases. For example, you can find all Order Shipment cases that were made by customers with platinum status who are ordering a particular brand of coffee.
The logic for tracking duplicate cases is implemented in your application as a case match rule that evaluates a set of weighted and exact conditions.