Trade official, source tells ESPN:

Bears get: Khalil Mack, a 2020 second-round round pick and a conditional 2020 fifth-round pick.

Raiders get: 2019 first-round pick, 2020 first-round pick, 2020 third-round pick, 2019 sixth-round pick.

So Bears get back second-round pick, too

— Adam Schefter (@AdamSchefter) September 1, 2018