A community coalescence framework is critical for deliberately merging microbial communities to perform specific functions. This framework considers how the mixing of environments and microbial communities result in a newly established community and set of ecosystem functions. Not only is it fascinating to develop a comprehensive understanding about how microbial systems operate when faced with the massive biotic disturbance of community coalescence, but rigorously testing this concept in engineered systems, including agricultural biostimulants and human probiotics, is vital for efficiently and effectively moving forward. The objectives of this session are to (1) examine how coalescence theory could inform the design of  microbial engineered systems, (2) discuss the abilities and limitations to predicting the outcome of coalescence in terms of community structure and function and identifying key features of microbiomes that enable success, and (3) identify future research, including the consequence of community similarity or of repeated mergings. on community coalescence outcome.