TBC is an acronym that stands for “To be confirmed”. It is used in the same capacity as “TBA” (to be announced), or “TBD” (to be decided or to be discussed).
TBC is often used in the UK for the same purposes as TBA and TBD. TBD and TBA are used more commonly in the USA and internationally.
In business settings, an author will often use “TBC” or “TBD” on diagrams and reports for details they are not yet sure about. They will first present a number of decided and certain items with complete details, and then item(s) which they are not yet sure about: TBC!
This example of a portfolio roadmap uses TBC here.