Dual-track agile, popularized by Marty Cagan and Jeff Patton building on Desiree Sy's early work at Alias, separates the activity of figuring out what to build from the activity of building it — without separating the people. The discovery track runs experiments, interviews, prototypes, and analysis to reduce risk on candidate ideas. The delivery track turns validated ideas into shippable, production-quality software. Both run continuously and in parallel, week over week.
The connecting mechanism is a single prioritized backlog. Discovery's job is to feed that backlog with items that have already cleared the risks that matter — value (will customers want it), usability, feasibility, and business viability. Delivery pulls from the top of that backlog. The team is the same group of people wearing different hats at different moments, not two staffed units.