https://en.wikipedia.org/wiki/Constitution_of_the_Confederat... clarifies a lot:

> The U.S. Constitution states in Article IV, Section 2, "The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in the several States." The Confederate Constitution added that a state government could not prohibit the rights of slave owners traveling or visiting from a different state with their slaves.

Similar to the Fugitive Slave Clause, this does not invalidate the Dred Scott opinion that "a State may unquestionably prohibit slavery within its territory."