In the continuity of the Arrowverse, this takes place two years after William Clayton's abduction in Green Arrow & the Canaries (2020).
Nora Darhk expresses sorrow at having to lose her father again, referencing the events of Mr. Parker's Cul-De-Sac (2020).
The restaurant "Robern's" at the beginning of the episode is a nod to Reverse-Flash's past - Robern Thawne was Eobard's younger brother. As a child, Eobard was jealous and angry at the attention his little brother received from their parents. As an adult, Robern worked in law enforcement and reported Eobard for unauthorized science experiments in his lab, which caused Reverse-Flash (watching his past life) to go back in time and prevent Robern from being born, erasing him from history.
Finally, a true to comic costume with the introduction of the gold boots, something the showrunners have been teasing for years.
Excluding the "Elseworlds" crossover, which was a one-off timeslot switch with Supergirl (2015), this is the last episode to air on Tuesday. Beginning with the spring premiere in 2022, the series will move to Wednesday nights.