The Wall Street Journal is reporting that Flynn is seeking immunity, but the WH say they haven't received any request from him officially. I certainly don't see anywhere saying that they have refused immunity.
From what I've read, he doesn't have anything to hide - he's just concerned the lying and other BS will land him in hot water. I don't think the bombshell will come from him, if anyone does it I think it'll be from Comey himself.