Reagan’s 1980 pick of Bush - an example of a conservative candidate picking a GOPe to unite the party and reach more voters in the election.
Cruz picking Rubio would do the same, along with the appeal to hispanics I mentioned.
I would much rather see Cruz not repeat Reagan’s mistake as both members of the Bush family set the GOP back. If an establishment candidate has to be picked I personally would much rather have Walker than Rubio. Jmo.