Sharepoint List Source:
Employee Name is Single Line Text,
Supervisor and Team is Dropdown

PowerApp;
My lookup formula is
LookUp('AV List','Employee Name'=ComboBox2.Selected.'Employee Name',Supervisor)

Error message is

My formula is working if the result source column (Supervisor) is a single line text field, but not if its different. Is there a documentation for this that I can read?