This market resolves YES if Jonathan Majors appears in Avengers: Secret Wars, and NO otherwise.
If Avengers: Secret Wars is never released, the market resolves N/A. If there are multiple Avengers: Secret Wars movies, such as if movies are titled Avengers: Secret Wars Part I and Avengers: Secret Wars Part II, appearances in either will count as YES.
If Majors appears only through archival footage, this market will most likely resolve NO, although if it is sufficiently difficult to determine whether new footage was filmed, it may resolve N/A.

If only a CGI body double of Majors appears, it will resolve NO unless it is clear that Majors was somehow directly involved in the film, such as by providing new vocal lines.

If our own universe is visited by a multiversal variant not of Kang but of the actual actor Jonathan Majors, who then acts in Avengers: Secret Wars, I am giving up, never resolving the market, and retiring to Tahiti. I hear it's a magical place.