How is the commission system similar to the council-manager system of government?

In the council-manager form of city government, the city council makes laws and broad policy decisions for the city manager and staff to carry out. 
the council-manager form of government “combines the strong political leadership of elected officials with the strong managerial experience of an appointed manager or administrator.

Commission government is a form of municipal government that vests all legislative and executive authority in a small board of commissioners. Elected at large, each commissioner is responsible for the administration of one branch of municipal business, such as public safety, public works, and finance

both the council- manager system and the commission system are similar in that they both elect officials