What were the ramifications of the slave trade, and the effects of the slave trade on society?
Because your question does not specify which society you are asking about, I will assume that you are asking about the ramifications of the slave trade for the United States.
The main ramification of the slave trade was the creation of a slave economy in the South that was a double-edged sword for the United States. The slave economy in the South was vital to the economic development of the early United States. Though slavery was confined to the South, companies and individuals in the North profited from slavery by selling goods and services to slaveowners and slave traders. The creation of the slave economy, however, came back to haunt the US when it led to the Civil War in the 1860s.
The slave trade also had significant ramifications that were felt by American society. Slavery helped to create an aristocratic social system in the South. Southern planters saw themselves as the equivalent of English aristocratic lords. They acted in many ways like those lords and they created a very stratified society with themselves at the top. Slavery (enabled by the slave trade) also helped to create a deep racial divide in our country. This racial divide continues to affect us to this day.
In these ways, the slave trade had serious impacts on our country and our society.