Philippians 2:5-11 is traditionally associated with the doctrine of the Trinity. However, I think the context suggests that Paul's main point is not to teach the doctrine of the Trinity. From an interpretative standpoint, I believe the context suggests that Paul intends to teach something about unity and our attitude towards other believers, and he uses Christ as an example to make that point. If we also learn something about the Trinity, that is icing on the cake.