Evolution is central to microbial ecology and therefore evolution may be a key driver of coalescence outcomes. Evolution provides microbes with familiarity with their community members. If community members evolve towards greater cohesiveness (to reduce negative interactions), we may expect such communities to outcompete others in which interactions are more negative. By understanding how microbes adapt to living within their own community, we may understand why some community members “stick together” during complex coalescence scenarios. And in applied settings, we may be able to engineer communities through evolution to displace diseased or unproductive microbial communities.