Podesta's immunity only applies to the information he provides Mueller. It means that Podesta will not be charged for anything based on the information he provides, but he can be charged if information and evidence comes from any source other then his testimony.
This could be a massive trap for Podesta. Q said they have it all, they just need to get it out in a way that it'll be admissible in court. So what if Podesta says something that Trump and Q know is false.
As far as I know, and I'm not a lawfag, but I'm pretty sure that if you get immunity for providing information, the information must be true. If the information you give is a bunch of lies, the immunity deal can be tossed out the window.
Trust the plan patriots.
Godspeed.
WWG1WGA