You will be asked behavioral type questions. These will follow the S.T.A.R model, which is basically you tell about a S(situation) or T(task), what A (action) you took in the situation, and R (Results) of the situation. Your answers will be measured based on the complexity, effort and scope of the situation. They except you to give clear answers about a situation that actually happened to you, it cannot be a hypothetical response. They will be looking for you to tell them about situations in which your leadership role had a positive result. Make sure you are not overly negative towards others in any part of your answers (like saying how you had to lead your peers one day because your TL sucks).
They will also ask some basic interview questions like "Why do you think you would be right for this role"?. The best thing to do is to find an ETL to prep. with because they have access to TL interview guides and will know most of the questions you will be asked.