The session covers nested structures in programming, building on previous topics of defining structures, declaring variables, initializing them, and accessing members with the dot operator. It explains how to include one structure as a member of another. For instance, a student structure is defined with ID, name, and a date of birth member. The date of birth is a separate structure containing day, month, and year. The approach requires defining the inner structure first, then incorporating it into the outer structure as a member.