When Frank is being carried from cell block A, they carry him over a puddle. In the middle of his chest, in a blood stain, is the Punisher skull.
When Frank Castle first meets Fisk working out in prison, Fisk is bench pressing 225 kg.
The word Kingpin is used a few times in the episode referring to Dutton and later Fisk. In the comics, Fisk's criminal alias is the Kingpin.
Hirochi refers to Murdock as "Akuma-San": Japanese for Devil Man.
When Karen Page enters Ben Urich's office several news articles are seen framed on the wall. There are a couple that reference other Marvel projects. One is titled, "Battle of NY" which references The Avengers (2012) and another is titled, "Harlem Terror" which references The Incredible Hulk (2008).