We know from the Infinity War prelude comics that the Soul Stone is possibly the most dangerous of all six Infinity Gems.
The official Infinity War trailer has brought with it a slew of new footage (much to the delight of the fans), but avoids revealing where the final Infinity Stone is.
Avengers: Infinity War directors Joe and Anthony Russo are also wondering where the Soul Stone is.
Director Ryan Coogler later explained that since Vibranium serves as the film’s MacGuffin, there simply wasn’t room for an Infinity Stone in Black Panther.