The new grand jury is a sign that the investigations are ramping up—it shows that the Russian investigation has expanded beyond Flynn to several of Trump’s family members and current and former aides and will possibly continue for many more months. It also means that criminal charges are possible (and that Mueller has evidence of possible criminal activity). It is as yet unclear who the targets of the investigation are.
Possible financial crimes
We know less about this prong than the other two. The Post reported last month that “in addition to possible coordination between the Kremlin and the Trump campaign to influence the 2016 presidential election, investigators are also looking broadly into possible financial crimes — but the people familiar with the matter, who were not authorized to speak publicly, did not specify who or what was being examined.”