Frost is shown reading "Uncage Desire," which was written by Mick Rory from DC's Legends of Tomorrow (2016).
Kamilla can be seen running experiments on Cicada's dagger, which had been sent into the Mirrorverse back in Season 5.
Danielle Panabaker's character, Killer Frost, can be seen hiding behind pillows and blankets. This was due to the fact that she was pregnant with her first child with husband N. Hayes Robbins. She announced the birth of their child on her Instagram page on April 2, 2020, about 5 weeks before this episode aired.
The way Godspeed runs around the side of a building to incapacitate The Flash is in the exactly the same way as in Into the Void (2019) except the roles are reversed.
In the new post-Crisis reality, Hartley has Mooks during his original confrontation with Flash. His enmity with Barry post-Crisis is due to Barry crippling his right-hand man (who is also his boyfriend) with lightning.