One example is, suppose you need to study how COVID-19 has affected the hospitality sector. In that case, you could pick out both a agent case, for instance a large hotel chain, or an outlier case, like a compact Mattress and Breakfast that has managed to outlive the pandemic. Basically https://knoxdbcqm.tinyblogging.com/the-definitive-guide-to-case-study-analysis-83195777