Matt, Karen and Foggy go to Josie's Bar at the beginning of the episode to celebrate the retirement of Detective Cherry. Josie the Bartender is played by Susan Varon and she returns for a cameo after being a regular in Seasons 1 & 2 of Demolidor (2015) and appearing in Os Defensores (2017) episode, Mean Right Hook (2017).
The attorney chatting with Foggy in Josie's Bar is Kristie McDuffie, a character from the comics who first appeared Daredevil (vol. 3) # 1 in July 2011. At the end of Season 3 of Netflix' Demolidor (2015) series, Foggy was engaged to his girlfriend Marci Stahl, but seem like the engagement was called off as he was chatting up Kristie.
The name of the law firm Matt Murdock, Foggy Nelson, and Karen Page works at is now called, 'Nelson Murdock & Page', the new name of the law firm Matt, Karen and Foggy wrote on a napkin in the final episode of Season 3 and series finale of the Netflix Demolidor (2015) series, A New Napkin (2018). Now their firm is firmly established with an actual sign reading, Nelson Murdock & Page.
The first painting shown during Vanessa's meeting is considered one of Russia's most famous and controversial paintings, and is by the Russian realist artist Ilya Repin. The painting is titled, "Ivan the Terrible and His Son Ivan on 16 Nov. 1581". Even though it was made between 1883 and 1885.
Wilson Fisk is seen eating a breakfast that is one egg white omelet with no yolk and a single asparagus which is meant to show why he has a slightly slimmer appearance in this series. In Season 1 of the Netflix Demolidor (2015) series, Wlson Fisk was shown cooking his own breakfast where he definitely kept the yolks in his eggs.