How would the world be different if the Columbian Exchange never happened?
Europe and the Old World would have had less agricultural products and the Americas would have had less animals products.
Europe would be much poorer in food crops without the Columbian Exchange. Potatoes a staple in Ireland, Vodka in Russia, and raised throughout Europe and Africa would not exist.
Corn or maize would not have been available to Europe and Africa. Maize quickly became the staple food crop in Africa. It was Maize that allowed the Bantu to spread from West Africa to dominate East and Southern Africa.
Italian cooking would not have Tomato sauce, no pizza, spaghetti, or other now "traditional " Italian dishes.
The Americas would have few domesticated animals. The horse that became ionic in the plains Indians came from Europe. Cows and Oxen would not provide meat, milk and in the past muscle for plowing and hauling would not exist. Even the humble chicken with its eggs would not be a source of protein.
The Americas would be much poorer without the Columbian Exchange. There would be few sources of animal protein beside hunting, Agriculture without the strength of domesticated animals were been much more limited.
Both the Old World and the New World benefited from the Columbian Exchange. The World is much richer for the exchange of ideas and products due to the Columbian Exchange.