After slow-paced revelations in the first two episodes, Hawkeye episode 3 finally brought Clint Barton and Kate Bishop into the action scenes that the promos promised. The latest episode also focused on Maya Lopez aka Echo and her backstory.
Her past is essential to the series and beyond, as she will soon have her solo Disney+ series, where she will be seen taking up the mantle of Echo.
The third episode of the series established the relationship between Kazimierz "Kazi" Kazimierczak/The Clown and the 'Tracksuit Mafia.' It also introduced a subplot that could show Clint Barton accepting his hearing impairment, as Maya Lopez suggested. It is plausible that his impairment and commitment towards family are the reason why Clint passed on the mantle of Hawkeye to Kate Bishop.
Easter eggs and theories that spawned from Hawkeye episode 3
Echo's past:
Maya Lopez is seen getting combat training from an early age while not letting being an amputee stop her from dominating her opponents.
Later, in her backstory, it is seen that she sees her father being murdered. The shot also included her father's bloody palm leaving a handprint on her face - this is a callback to the comics, where she paints a handprint on her face while portraying her alter-ego, Echo.
Uncle:
During Maya Lopez's backstory, a character is seen visiting her in school. While the character's face was not shown, it resembled the likes of Vincent D'Onofrio's Wilson Fisk (aka Kingpin) from the Marvel X Netflix Daredevil series. Rumors of his character making an appearance in the show have been doing the rounds for months, and Echo's relationship with the antagonist in the comic only makes it more likely for him to do so.
Furthermore, later in the episode, Kazimierz "Kazi" Kazimierczak mentioned an 'uncle,' who is likely to be Fisk. Maya's father worked with him in the comics and was killed by the Kingpin, who framed Daredevil for his death.
D'Onofrio is also rumored to appear in the upcoming Echo series with Maya Lopez (portrayed by Alaqua Cox).
USB arrows:
First seen in 2012's The Avengers, the USB arrow made another appearance after being briefly featured in What...If?
The interaction between Kate Bishop and Clint Barton appears to have been taken right out of the comics when Kate mocks the function of this specific arrow.
Hawkeye's 1970 Dodge Charger:
The car was featured heavily in the episode's chase sequence. However, it was totalled in the end, much to Clint's chagrin. He bought the car from Ivan's wife, Cherry (aka Darlene Wright) in the comics.
The episode also showcased the extent of Hawkeye's hearing impairment and had several comic book references to the 'Tracksuit Mafia' as well as their front business of moving and relocating services called "Trust A Bro."
Future episodes may finally tie up the Yelena Belova subplot from Black Widow's post-credit scene.