Before the cloud
As always, it's best to start with a bit of perspective. Whether you've begun reshaping your IT environment and organization to be cloud native, or are yet to embark on the journey, you need to understand how the majority of organizations are organized to design, build, and run current IT systems.
As an example, let's consider an insurance company that offers several products to its customer base (home, life, and auto insurance). Internally, it has several teams, which help support its products: policy developers, field sales teams, statisticians, HR, programmers, marketing, actuaries, and so on. Each of these teams consumes the services of the IT team (whether it's servers for emails, clusters to run statistical models, databases to store client information, or websites to be a storefront for the public).
The IT team is in turn separated into several groups based on domain competencies. Network, security, database, and ops are typical teams found in these outdated organization...