What is the role of Cisco ISE (Identity Services Engine) in a network?

Cisco ise is an advance centralized network authentication authorization accounting appliance. 

it has almost all the feature for which acs is used i.e 

all devices whenever accessed they are authenticated by a user and according to that users profile he is authorized .

Ise can also be used to limiti the kind of traffic allowed for a user according to their profile which can be created manually or ise can use its sensors also to dynamically create a profile according to the user type like android phone can be give access for web only , no telnet ssh is allowed for them .