In Creed II, as Adonis is preparing to propose to Bianca, he asks Rocky how he did it.
(These events played out way back in 1979’s Rocky II.)
The “Italian Stallion” digs into the damaged memory banks of his brain and starts to recall being at the zoo with Adrian, on a cold and snowy day.
So when it’s time to land on his own life moments, Adonis turns to Rocky to ask for advice, and in the process we pick up more information on Rocky’s own backstory.