Planet formation on the outer disk

In this talk I will review our current understanding of planet formation on the outer parts of the protoplanetary disk. We will address questions such as: what type of planetary compositions do we expect? What are the differences with planet formation in the inner disk? Is there a type of planet formation model (e.g pebble vs. planetesimal accretion) that provides a better match with observations? Are there observational trends that we cannot explain? What theoretical challenges do we still face? What new observational constraints will arise in the next years?