Do people have rights to immigrate? Most people think: no. I think: yes. But let's get clear on what this means.
In international law and the domestic laws of some liberal states, there is a limited special right to immigrate. Asylum-seekers have this right. It is the right to flee from tyrannical regimes and rights violations. But people don't have a general right to immigrate. For example, "economic migrants" do not have rights to immigrate. These are people who just want more economic opportunities.
If you accept a certain understanding of the justification of rights to immigrate, then this conventional view makes sense. On the common understanding, rights to immigrate are justified on grounds of beneficence. States are morally required to let people immigrate because this is necessary to save them from violence or severe hardship. But we aren't under duties to better people's economic opportunities in general. I'm not obligated to help you find a better job if you're already making $20,000 a year.
This conventional view already presupposes that states have territorial rights: rights to coercively exclude certain people. In other words, if a state has already satisfied its humanitarian duties to you, this state can now freely prevent you from immigrating to its territory. So, the only reason (besides family reunification, say) to permit immigration is beneficence.
However, this conventional view is false. I'll explain why in future posts.