Sessions has
some wiggle room on perjury accusations, but looks close enough for a trial to me. It's going to come down to the contents of any conversation and the exact wording of the questions and responses.
The arguments are that the contents of his conversations with the ambassador do not match the context of the questions he was asked, although one story reports that the context was at least extremely similar in one of the questions (eg, they discussed the election). At first glance it looks like enough to get him off, but there are potentially still shoes waiting to drop (FBI investigation appears to be into other conversations than those discussed so far) and a couple of different questions he answered which could be enough to screw him.
Sadly in this case a trial would mean impeachment hearings, which would mean at the least a dozen Republican Senators pulling out the long knives on one of their long-time colleagues and friends.
Remember that this means Trump appointed a man to oversee the FBI who the FBI was currently investigating. Trump should have been privy to that information, but appointed Sessions anyway. Again, the lie in incidental to the fact that he is the wrong man for the job, and Trump wanted him over all other qualified candidates anyway.
As for what happens with Sessions, I suppose it depends on what exactly was said. Plus increased calls for a special prosecutor.
I'll try to pull some links later, but there are good reasons to want an independent commission over a special counsel.