The $2 billion revitalization effort known as Greater College Park is centered on Baltimore Avenue, but the latest major addition is invisible from the road.

Tucked under the parking garage behind the Hotel at the University of Maryland is a glassed-in, wired-up, tricked-out innovation hub called the Diamondback Garage—a 20,000-square-foot space where student startups mix with Fortune 500 firms and an “entrepreneurial ecosystem” is strengthening its campus roots.