The rumors existed and with episode 5 of the TV series, they were confirmed: Wilson Fisk, the Kingpin himself, is now part of the MCU. However, it was in the season finale that we learned more about this character.
The appearance of the big bad was the perfect time for Clint Barton and his apprentice, Kate Bishop, to join forces again to take down the villains in a sequence of memorable action scenes outside of Rockefeller Center.
(I had to add this image, give me more of these two)
From Yelena seeking revenge for her sister to the Tracksuit Mafia led by Maya Lopez, this episode packed all the rivalries against Hawkeye into about an hour. All this with Fisk pulling the strings, of course.
The episode opens with Kingpin saying the line "the people need to be reminded that this city belongs to me," which sets up the season finale as an explosive one. The first confrontation is between Fisk and Kate Bishop after the villain goes after Eleanor Bishop for her latest business decisions. Indeed, the fight ends in a huge explosion.
Later, Maya appears on the scene and tries to convince her friend Kazi to escape together, but he, knowing that this is his only way to live, forces Maya to kill him.
Maya then confronts Fisk, who appears injured from the explosion, but still alive. In the end, she apparently shoots him (in the face?), but the camera focuses elsewhere, not showing whether he is alive or not.
The other major confrontation was between Yelena and Barton, who manages to convince her that Natasha sacrificed herself for everyone when he uses the sisters' secret whistle. Telling her about past events that Natasha had told him, Clint manages to pacify Yelena, who helps him to get up and then says goodbye.
We are not sure when we will see some of these characters again. For one thing, we don't know if the Kingpin is still alive, but everything points to yes. Yelena could very well appear as part of the Young Avengers in the future alongside Kate Bishop. It is already certain that Maya will have her series in the MCU, which will hopefully explore much more about her relationship with the mafia and her transformation to the anti-hero, Echo.
On the other hand, Hawkeye could appear as a recurring character in the MCU, gradually giving way to a younger generation of heroes. However, everything remains to be seen in an MCU that promises more and more.