Kaylee Ehrmantraut is Mike Ehrmantraut's granddaughter. She and Mike share a strong bond, including playing games such as Hungry Hungry Hippos with each other. This bond is further shown when Mike is clearly visibly upset during his DEA interview with Hank Schrader and Steven Gomez when they proceed to inquire as to who she is and threaten the trust fund Mike had set up for her.
In an interview with Jonathan Banks, he stated that in his vision, Mike wouldn't have left Kaylee in the playground when the DEA found him. But he accepted the scene as it was, since he respects the writers.
Kaylee playing a game with her grandfather ("Madrigal").