They are independent and would simply compete as to which tripped first as they both operate on the same principle - much like putting 2 fuses in line. GFCI breakers detect when the hot and neutral wires don't have the same current in opposite directions, indicating a loss of current to ground (hence ground-fault) usually a few milliamps of difference.
The GFCI breaker will protect the entire branch while the GFCI receptacle will only protect that receptacle, but if it trips it means a longer walk to the breaker box to reset it. The other advantage of the GFCI receptacle is that it is easier to test and the user will know the items in the receptacle are protected.