As mentioned earlier, CPS, CPI and CPL are different types of campaigns run by merchants with Cuelinks.
CPS stands for Cost Per Sale: It is the commission paid out to you for every successful sale made via your affiliate links.
CPI stands for Cost Per Install: It is the commission paid out to you for every successful mobile app installation / some action done after installing the app via your affiliate links.
CPL stands for Cost Per Lead: It is the commission paid out to you for every successful lead generated via your affiliate links. A lead can be a sign-up, form submission, or other specific actions taken by the customer on the merchant's site, which may or may not result in an immediate sale.