A 2017 presentation from the Future of Humanity Institute, University of Oxford.  In summary:

• The Fermi question is not a paradox: it just looks like one if one is overconfident in how well we know the Drake equation parameters.
• Doing a distribution model shows that even existing literature allows for a substantial probability of very little life, and a more cautious prior gives a significant probability for rare life.
• The Fermi observation makes the most uncertain priors move strongly, reinforcing the rare life guess and an early great filter.