Most fans have been wondering where are all the new MCU characters.Well, the answer is hidden inside the (totally amazing, spectacular, awesome etc, etc) Captain America: civil War trailer.
If you look closely you'll see that, approximately, every sign is written in german ("polizei" is "police" in german but it might also mean the same in another north european country) and maybe "IFID" is "Institut de Financement du Développement du Maghreb Arabe", which is "Institute of the Arab Maghreb Development Finance" (according to google), which locates in Tunisia. That might be the place where "Wakanda" is so Marvel can introduce Black panther.
If those matters are true then all the missing heroes are justifiably missing from the trailer. They all live in USA, they have no reason to be in Germany or Tunisia.
That's what I think has happened, what do YOU think?