Batman: Family Vol 1 1: Perception
This is the first part of an eight part storyline and Cass is spoken about, but not actually showing up, so let me just sum up the issue quickly: a strange new vigilante called Tracker has appeared in Gotham. He is working together with a strange, secret organization and the villain Suicide King, and is systematically taking out the corrupt Rossetti family. He dies at the end of the first issue, where we also find out that the newly appointed head of Wayne enterprises, a woman called Cecilia, is the Tracker’s mother and is trying to bring down Wayne Enterprises and Gotham with the help of this secret organization.
Now, when the Wayne Enterprises’ board of directors first decides to have Bruce removed as president, Bruce tells Robin he is planning to step down, since it will also give him more time for his vigilante job. Robin argues that Bruce could just keep on going as is, just by letting the family handle the crime-fighting for a while, specifically mentioning that Superman relies on Supergirl plenty of times and thus implying that Cass could do Bruce’s job just as well. It is great to see how far Tim has come in appreciating her since they first met (remember that Tim was really freaked out by her and did not trust Cass).