In this session, you will learn about the concept of "endotyping" (splitting a heterogeneous disease into homogenous subgroups with common pathophysiology) and how it can allow for more effective, personalized medicine in lung diseases. Examples of endotypes in various lung diseases including lung cancer, ARDS, and asthma will be discussed. The implications of this concept will be explored in greater depth for COPD with an emphasis on emerging evidence supporting tailored therapy for COPD endotypes.