This variant was originally shipped in a plain opaque polybag wrapper without any reveal of the cover artwork during the solicitation period. Hence the description of "secret cover."
This issue is a variant of Age of X-Man: The Amazing Nightcrawler (Marvel, 2019 series) #1 [Shane Davis].
There exist further variants:
Contracted by NASA to produce footage of the first manned moon landing and save face for the sitting president, Nightcrawler voiced his objections on a Studio X soundstage.