Some questions you could ask yourself are:
- Does the team know Agile, the Scrum framework?
- What is the composition of the team?
- What motivates the members?
- What are the common goals of the team?
- How about the values of the team?
- Is there a history that we need to know before joining the team?
- Would you start with a kick off / retrospective where the team would explain their pains and where we could discuss