Lewis, 60, led the Bengals to a 6-10 record this season. The Bengals were 131-122-3 during Lewis' tenure. The AFC North franchise was 0-7 in the postseason under Lewis.
The Bengals had the worst defense in terms of yards allowed in 2018. Cincinnati also allowed the most passing yards and third-most rushing yards in the NFL. The Bengals ranked 24th in passing offense and 21st in rushing offense.
The team has yet to officially announce the move.