Agencies of the Commonwealth; law-enforcement agencies; employees and officers; agreements with federal authority for immigration enforcement; prohibitions and limitations. Prohibits a state agency or a law-enforcement agency, defined in the bill, from entering into a written agreement authorizing any employee or law-enforcement officer to perform a function of a federal immigration officer. The bill provides that federal immigration laws shall be enforced by a state or local law-enforcement agency of the Commonwealth pursuant to a valid judicial warrant, federal or statutory regulations, or as otherwise required by state law. The bill also prohibits an employee of a state agency or a law-enforcement officer, defined in the bill, from conducting certain actions or inquiries regarding a person's citizenship or immigration status while engaged in the performance of his duties and creates a cause of action for appropriate equitable, injunctive, or declaratory relief against such employee or law-enforcement officer who willfully conducts such actions or inquiries in violation of the provisions of the bill. Finally, the bill requires any state agency or law-enforcement agency that has an existing written agreement with a federal authority to perform federal immigration functions to terminate such written agreement by September 1, 2026.