When Fisk takes Vanessa Marianna on a date, she describes a prince she dated once before, saying he wore a white suit and an ascot, to which Fisk replies: "Ascot? That's a bit much." This is a hint at the classic Kingpin look of the comics, where he often is depicted wearing exactly such an outfit.
When Matt is on the bench in the police station, over his shoulder can be seen the following sign, "You don't have to reveal your identity to help solve violent crime."
Claire Temple asks Matt Murdock: "Are you one of those billionaire playboys I've heard about?" This is a sly reference to the Tony Stark character, who is publicly Iron Man and fights crime in this costumed identity and is a billionaire and part of the MCU. This could also be a tongue-in-cheek reference to Batman from the DCU, as his secret identity Bruce Wayne is often called a "billionaire playboy."
When Matt Murdock describes to Claire Temple how he can "see", he uses the metaphor of an impressionistic painting as seeing the world on fire. This is another parallel between him and Wilson Fisk who felt alone in the snowstorm of the white painting seen in Rabbit in a Snowstorm (2015). It's the ice of Fisk vs the fire of Murdock.
When Karen is hitting the copier at Foggy and Matt's practice, Foggy says "Whoa, be nice to it, you know, for when the machines take over," hinting at Ultron's takeover of technology in Avengers: Age of Ultron (2015).