At one time states were responsible for immigration. Many of my ancestors went through Castle Garden at the lower tip of Manhattan. The Supreme Court ruled that the federal government had jurisdiction. That was when Ellis Island was constructed.
Many cities and the state of California have decided that can ignore federal law by not cooperating with immigration authorities. I don’t see a problem with telling police not to ask people about their immigration status. Refusing to hold people being released from jail is another matter. I fail to understand why they go to such lengths to keep convicted criminals in their midst. One city includes killers unless it was first degree murder. Their desire to help these criminals outweighs their concern for the safety of its residents.
Of greater concern is the idea that a state or local government can pick and choose what federal laws they have to obey. If this is the case, then presumably they have the right to violate our constitutional rights or arrest federal employees for carrying out their responsibilities.
This is a totally separate issue from immigration reform. Personally, I think there is a solution somewhere between the Trump hardline approach and those that want to open the floodgates. Unfortunately, both sides are more interested in fighting each other than coming up with an effective compromise.