#1 Champions League Glory

As I said earlier, a Champions League trophy is rated above a domestic double, and this makes Ronaldo a clear-cut favorite to win the Ballon'dOr. One can claim that Real Madrid has carried Ronaldo through the La Liga games, but UCL has been totally vice-versa.
Ronaldo has scored in every group game in the Champions League, being the first man to do so, and his contributions for the Bernabeu outfit is incomparable.
Though he was not as good in the semifinals and finals of the Champions League, his goals in the earlier stages of the tournament have saved Real Madrid abundant times. Ronaldo with Real Madrid has won 3 back to back UCL trophies, making it a total of 5 in his 9 years of absolute brilliance and magic for the Los Blancos side.
As I said before, a Champions League trophy gives him a definite step ahead of the likes of Mbappe, Griezmann, and Messi, to win the Ballon'dOr 2018.

The nine substantial years he has played for the Bernabeu is enough to determine his greatness in the footballing world, as the Portuguese broke records in profusion in that time span.