With the explosive growth of new technologies such as 5G, large-scale AI models, and network coding, transport layer protocols face unprecedented challenges in scenario adaptation, driving numerous cutting-edge technological innovations. For emerging scenarios demanding high concurrency, low latency, and high reliability—such as mobile networks, data centers, and high-performance computing—traditional protocols struggle to meet requirements, necessitating targeted protocol optimization and innovation. The network landscape is constantly evolving, with the transport layer transcending the constraints of traditional protocols to meet the high-performance demands of the 5G, data center, and AI eras. This chapter explores the development and optimization of transport protocols in cutting-edge domains, delving into transport layer innovations under future network architectures like MIN. Finally, it guides students to explore and contemplate the future direction of next-generation transport protocols through a thought-provoking question and discussion centered on future-oriented network protocol design principles.