The Mission impossible movies are meant to function essentially like the Bond movies, with the main plot of each story being self contained. The only thing that really continues from movie to movie are the ensemble characters and their roles, such as Simon Pegg or Jeremy Renner who joining in MI:III. However you could ignore the movies and still generally ...
In Mission Impossible 2, the ONLY thing that is continued or relevant to MI series is, assigning a mission to Agent Hunt and his helper Luther Stickell.
All other things including Characters, Villian, Scenes or girlfriend. (wife is not mentioned at all) are different. So theoretically, it's an independent script of the series.
Some of us will say, MI:3 is ...
Straight from IMDB:
Nekhorvich felt that this was the most viable way of getting the virus
to the Center for Disease Control (CDC) in Atlanta, i.e., providing it
with its optimum environment (in the human body), lessening the
chances of losing or breaking a vial, contaminating others, and
perhaps the virus being discovered in his baggage by ...