The Netflix shows have always been part of the MCU from Jump. During the months leading up to the airing of these shows many fans had asked and it was said that they were. Fans had also asked if there would be any crossovers between Netflix and the Movies and the answer was, "maybe but most likely not, it would depend". Also in the Netflix shows the NY battle that happened in the Avengers movie was reference several times as "The Incident".
Also on Wikipedia, "Produced by Marvel Television and ABC Studios, they are set in the Marvel Cinematic Universe (MCU) and acknowledge the continuity of the franchise's films and other television series. "
https://en.wikipedia.org/wiki/Marvel's_Netflix_television_series
Interview with a Netflix DD producer back in 2015. Around the 6 min mark he says "Marvel was very supportive in wanting this to be a darker corner of the MCU". Also near the end at around 27:40 mark, the interviewer asked, "Could we see DD and Kingpin in one of the movies meeting the other characters?"
