On November 15, 2021, the Computational Communication Research Cluster held the second event in its roundtable forum series. Dr. HU Daning from the Southern University of Science and Technology, Shenzhen, China, Dr. YAN Jiaqi from Nanjing University, China, and Dr. FAN Yi from National University of Singapore were invited to introduce their representative works regarding causal inference from observational data and answered questions from the audience. Dr. LIU Xiaofan from the COM department moderated the discussion. The event was held in a mixed mode of offline and online, with approximately 100 online participants locally and internationally.