 As with many Marvel projects , secrecy was a big issue . For instance , it was a challenge keeping Samuel L. Jackson 's cameo in " 0 @-@ 8 @-@ 4 " a surprise due to " this age of tweets and spoilers " . The showrunners had been exposed to this while working on The Avengers , but with their own series they were able to see " all the details that go into keeping everything under lock and key " . 
