The Mobile Network Operators (MNOs) around the world are facing unprecedented difficulties in 5G deployment. Restricted by the expensive spectrum resources, high investment, and high energy consumption of 5G, the profit gap between operators and equipment manufacturers is growing, and a large number of “business increment with no revenue increasing” problems are arising. How to reduce the cost of network construction and operation and how to adapt to climate change mitigation and enable the rapid benefits of 5G especially in the underdeveloped communications regions, imposes a major challenge to the global industry and operators. This Recommendation identifies the specification of 5G network sharing and co-construction and the contribution of 5G network sharing and co-construction to climate change mitigation, provides the key technologies of 5G network sharing and co-construction and explain how to make assessment of these technologies to adapt to the climate change. It also addresses the cost-benefit analysis and best practice of 5G network sharing and co-construction.