This is controlled by a menu option - CorePortal - Manager Appointment Salary - which can be enabled/disabled via Security.
Menu option name: CorePortal - Manager Appointment Salary
Menu ID: MAIN_MENU.Man_App_Sal
System: CorePortal
Unique menu option reference: 337360
In Security Dashboard, click on Menu Profiles tab
Enter name of relevant menu profile (e.g. COREPORTAL_MANAGER) and search
Click on the three-dot ellipsis and select Manage Menu Options on this menu profile
Enter CorePortal - Manager Appointment Salary in search bar
You should see Menu Option = CorePortal - Manager Appointment Salary and Menu ID = MAIN_MENU.Man_App_Sal
Ensure this menu item has its Active toggle switched off if employee salary details should be hidden from a Manager's view.
Please ensure that the below menu option is disabled for the manager as well
CorePortal - Administrator Appointment Salary