USFigureSkating.org has a press release with the 2020 Four Continents and Worlds assignments posted under tbe "News" tab. The Ladies assignments were announced previously, so I'm not typing them out here. They are included in the new press release.
Men to Worlds: Chen, Brown, Zhou
Alternates in order: Hiwatashi, Torgashev, Pulkinen
Men to Four Continents: Brown, Hiwatashi, Pulkinen (Torgashev to Jr Worlds selection camp)
Alternates in order: Krasnozhon
Pairs to Worlds: Knierims, Cain-Gribble/LeDuc
Alternates in order: Calalang/Johnson, Kayne/O'Shea, Denney/Frazier
Pairs to Four Continents: Knierims, Calalang/Johnson, Kayne/O'Shea
Alternates in order: Denney/Frazier, Lu/Mitrofanov, Serafini/Tran
Ice Dancers to Worlds:
Chock/Bates, Hubbell/Donahue, Hawayek/Baker
Alternates in order: Carreira/Ponomarenko, Green/Parsons, McNamara/Carpenter
Ice Dancers to Four Continents: Same as Worlds assignments
Men to Worlds: Chen, Brown, Zhou
Alternates in order: Hiwatashi, Torgashev, Pulkinen
Men to Four Continents: Brown, Hiwatashi, Pulkinen (Torgashev to Jr Worlds selection camp)
Alternates in order: Krasnozhon
Pairs to Worlds: Knierims, Cain-Gribble/LeDuc
Alternates in order: Calalang/Johnson, Kayne/O'Shea, Denney/Frazier
Pairs to Four Continents: Knierims, Calalang/Johnson, Kayne/O'Shea
Alternates in order: Denney/Frazier, Lu/Mitrofanov, Serafini/Tran
Ice Dancers to Worlds:
Chock/Bates, Hubbell/Donahue, Hawayek/Baker
Alternates in order: Carreira/Ponomarenko, Green/Parsons, McNamara/Carpenter
Ice Dancers to Four Continents: Same as Worlds assignments