I have two thrid party apps for integration. What is the use of SAP CPI here ?

Hi Guys,

hope all are fine.

I am having a doubt that i am having 2 third party apps. I want to integrate them. So how can i use SAP CPI for this scenario and do i have to deploy any one application in sap CPI or without deploying can i integrate these two apps?

Please give a brief and Simple explanation