You are asked what do you know about the history of the company, then they'll give you a chance to talk about yourself i.e. your past experiences etc. The interviewer asked data structures questions i.e. what is the purpose of a tree (Binary Tree). They'll ask questions about general iOS and Computer Science questions like What is ARC, explain MVC/MVVM, Explain what each letter stands in MVC and what they are etc. Compare and contrast MVC and MVVM.