How do I add CBX to my flight?

Excuse me, could you please clarify how one might go about adding CBX to their flight itinerary? I'm a bit confused as to whether CBX refers to a specific airline code, a service upgrade, or perhaps a new feature that some airlines offer. Is it a straightforward process that can be done online or through customer service? I'd appreciate any information you could provide to help me better understand the process of incorporating CBX into my travel plans.