It's a phrase used to express that someone else shares the same sentiment, experience, or action as the speaker.
For example:
* "Me gusta el helado." (I like ice cream.)
* "Y tú también?" (And you too?)
Here are some other contexts where you might hear "y tú también":
* "Estoy cansado." (I'm tired.)
* "Y tú también." (You too.)
* "Feliz cumpleaños!" (Happy birthday!)
* "Y tú también!" (Happy birthday to you too!)
The phrase is commonly used in both formal and informal situations.