By default, Kaspersky Who Calls marks incoming spam calls as SPAM! but doesn't block them. You can configure the app to block spam calls automatically.
To block spam calls:
In the navigation bar, tap .
Tap Incoming calls.
In the Automatic blocking section, tap Call blocking mode.
Block all spam calls. Calls marked as spam will be blocked automatically. You can see blocked calls in your call log.
Block selected categories of spam. Calls from spam categories specified by you below on this screen will be blocked automatically. You can see blocked calls in your call log.
The full list of categories for blocking is available only in the Premium version of Kaspersky Who Calls.