Why is there an ad after call ends?

[Android Central Question]

I have a galaxy s9 on ATT.

Whenever a call of mine ends, there is the usual screen I used to see on my s7 but on the s9 there is also an ad.

A) why does this even exist?
B) can I get rid of it?

Thanks!

 

[B. Diddy]

Welcome to Android Central! What do you mean the usual screen -- the lockscreen? This behavior is common for certain 3rd party apps, like flashlights, file managers, "phone cleaners" or "RAM boosters," etc.