While previous chapters provide a thorough description on differential privacy and presents several applications in reality, many interesting and promising issues remain unexplored. The development of social networks provides great opportunities for research on privacy-preserving but also presents a challenge in effective utilization of the large volume of data. There are still other topics that need to be considered in differential privacy, and we consider a few directions, including adaptive data analysis, personalized privacy, multiparty computation, differentially private mechanism design, private genetic data, local differential privacy and learning model publishing