There are a number of questions about how Christians should relate to the OT. It might be how to interpret/use the laws, it might be about the usefulness of the OT in general, it might be about typology, or prophecy or many different things.
- How is ignoring clear Biblical instructions in Leviticus justified?
- To what extent does the Law of Moses still apply?
- How does the Snake in the Desert foreshadow the coming of Jesus?
- Biblical Prophecy and Fulfillment
I feel like it would be useful to have a general tag for how Christians use the OT, but I'm not sure what it should be called.
One option is something related to the discipline of Biblical Theology, which focuses on the progressive revelation of the Bible, but it's a much more specific topic than may be appropriate for some of these questions.