The Kanem-Borno Empire prospered due to its control over

The Kanem-Borno Empire prospered due to its control over the salt trade.
Salt was an incredibly valuable commodity during ancient times because it was not only used as a seasoning for food, but also as a preservative to prevent food spoilage. It was therefore in high demand, and societies that controlled its production and distribution held significant economic and political power.
The Kanem-Borno Empire was strategically located in the Sahel region of Africa, which was an important crossroads for trade routes linking different parts of the continent. This enabled the empire to control the trade of salt coming from the desert regions to the north and distribute it to other regions in exchange for various goods and resources.
By monopolizing the salt trade, the Kanem-Borno Empire accumulated great wealth and built strong economic foundations. This allowed them to establish a prosperous and thriving civilization, supporting the growth of cities, the development of agricultural techniques, and the expansion of their influence in the region.
While other trades such as ivory, gold, and copper were also important, it was the control over the salt trade that played a crucial role in the empire's success.