During the Battle of Wakanda in Avengers: Infinity War, Captain America and Black Panther lead the charge against the Black Order and the Outriders. This scene gave rise to the fan theory that the two heroes have similar powers and that they both received their powers from the Heart-Shaped Herb.
Captain America’s power comes from the Super Soldier Serum, which was created by Dr. Abraham Erskine. The doctor’s first attempt to make a super soldier failed, leading to the creation of the Red Skull. After teaming up with Howard Stark, Erskine perfected the serum. Thereafter, the formula was successful in turning Steve Rogers into Captain America.
Howard Stark gave Captain America his infamous shield, which is made of vibranium. However, vibranium is only found in Wakanda. So, according to this theory, Stark would have been the one to hear about Black Panther’s powers and eventually acquire the Heart-Shaped Herb to perfect the Super Soldier Serum.