The Eagles' last two late-season runs have been something wild. Last season, they won the Super Bowl behind Nick Foles after Carson Wentz suffered an injury. This season, Wentz was injured again and Foles powered the Eagles into the playoffs, upsetting the Bears in the wild-card round before losing to the Saints in the divisional round.
Eagles head coach Doug Pederson had a perfect system implemented for Foles to thrive in. Foles didn't put up world-beating numbers, but he played well and gave the Eagles chances to win. Foles may end up generating some interest for QB-needy teams this offseason, and the Eagles have a decision looming on if they want to pick up Foles' 2019 mutual option.
After the 20-14 loss to the Saints, however, Pederson had an air of finality talking about Foles' time with the Eagles.
Presuming that Wentz is healthy next year, he'll almost certainly be back under center for the Eagles. Foles is an insurance policy, and a really good one at that. He's built a bit of a myth around him backing up for the Eagles, and he's earned it.