Churches will tend to have offical positions on matters that are related to morality (as understood by the church). This includes matters of sexual behaviour and abortion. But churches don't tend to adopt official positions on political questions that are economic rather than moral.
And the question of whether the USA should increase or decrease the number of migrants from Latin America is not primarily a moral question, but an economic one.
There is more of a moral element in matters relating to refugees and there are churches with missions to support (and convert) refugees. For example the United Church of Christ. There is a biblical tradition that Jesus' family sought asylum in Egypt after escaping from Herod. So there is a moral element to matters relating to displaced peoples.
Beyond that, churches are a reflection of the opinions of their members, and so churches. Churches that have a more conservative congregation will tend to reflect that, for example the LDS church position is more focused on the right of nations to enforce their laws.