A POC can notProof of Concept (POC) cannot be estimated in terms of story points, hours, ornor any sizing you use, since it is all about trying to prove if a suggested model works or not. That's why, it can notcannot be included in a sprintSprint.
As far as I understand, the need to include it in the sprintsSprints arises since;due to:
- some of the resourcesDevelopers in the scrum teamScrum Team will be working on that POC
- the output of the POC will be epics, stories, and/or tasks for the scrum teamScrum Team
You should approach this POC just like how you approach to a bug from the production environment; have a kanbanKanban board for these kind of activities and add the POC there. In terms of the workload of the scrum teamScrum Team members, you can use the same model you use when a member uses a paid time off ( vacation vacation).
I would recommend the PO to do the communication between the external and internal teams because the POC is mainly done for the PO; the outputs of it will define what needs to be done. While the POs doPO does the communication, they can do the planning to act faster.