Why do Sierra Leone and Tanzania have different countries?

Sierra Leone and Tanzania are distinct nations due to their unique historical, cultural, and geographical contexts. Sierra Leone, located in West Africa, was established primarily as a British colony for freed slaves in the late 18th century, leading to a diverse society influenced by various ethnic groups. In contrast, Tanzania, formed from the union of Tanganyika and Zanzibar in 1964, has a history shaped by Arab trade, German colonialism, and British rule, resulting in a different cultural and political landscape. These differing historical trajectories have led to the formation of two separate countries with their own identities.