The Chicago Bears convinced Brad Childress to come out of retirement in 2018.

Childress jumped on as an "offensive consultant" and it seemed to work for the first year, however after last year's disappointing offense it didn't work so well. 

So Childress has informed head coach Matt Nagy and the Bears that he won't be returning. 

As per Cleveland.com:

"Brad Childress has already told Bears coach Matt Nagy that he’s not returning in 2020 as his senior offensive assistant, presumably to retire, Childress told cleveland.com. But he acknowledged there’s at least a remote possibility he’d come back to Cleveland and help his protege Kevin Stefanski in his first season as Browns head coach if he reaches out."

That's it, that's all for Childress in Chicago and possibly in the NFL. 

Source: Cleveland.com