In general, something like "What's to be?", "What's to be done?", "What are we going to do about it?" "What is going to happen?"
In your example, "What are you going to do about it? Will you keep arriving late at work?"
1) (Ε,) τι να γίνει;... = What can be done? (The question is rhetorical, usually)
-It has been raining for 5 days in a row!
-Εεε, τι να γίνει... This, too, shall pass...
2) Τι θα γίνει;
Like Acestor showed at the end of their message, this is usually said when the speaker is irritated/annoyed because the other person keeps doing something that the speaker considers to be wrong. Expanding on Ancestor's example a bit:
-Good morning, boss, sorry I'm late.
-This is the 2nd time you're late this week! Τι θα γίνει; Will you keep doing that? Do you want me to fire you?