Press Enter to enter group edit context
When selecting a group you should be able to enter the grouped elements by pressing Enter key.
Sometimes it's difficult to double click (especially when using pen) the group to enter it without moving the object. When you'll be able to open the group using Enter key it will speed-up design.
Pooya K commented
Yes I totally agree, I'm using pen and it's harder to double click layer to rename it, it's better to use a shortcut like "Enter". selecting element from artboard or layer panel > Press Enter to rename.