What was Congress prohibited from doing under the Constitution until 1808?

The federal government could not interfere with the importation of slaves to the slave states until 1808. The context of the time was that most countries were already banning the slave trade, but the slave states wanted a few more years. Slave importation could be simplified into slave trade. The people were complaining that the government was butting into their lives to much so they made things like this for example.