A gas turbine engine component comprising: an external wall extending in a thickness direction (T) between first and second wall surfaces, the first wall surface bounding an internal cavity , the external wall surface establishing an external surface contour and at least one surface depression along the external surface contour , the at least one surface depression having concave geometry established by upstream (174-1, 274-1, 474-1) and downstream (174-2, 274-2, 474-2) arcuate faces sloping inwardly from opposed sides of a rim along the external surface contour to join at a valley , wherein the valley is established at a maximum depth (DM) of the at least one surface depression relative to the rim ; wherein the external wall includes at least one cooling passage extending along a longitudinal axis (LA) between an inlet port and an outlet port , the outlet port is established along the upstream face (174-1, 274-1, 474-1) of the at least one surface depression , and the at least one cooling passage is oriented such that a projection of the longitudinal axis (LA) has a component that extends in a direction (D1) towards the downstream face (174-2, 274-2, 474-2); wherein the at least one surface depression expands outwardly from the valley to establish a diffuser , and the at least one cooling passage interconnects the internal cavity and the diffuser ; and characterized in that the component is an airfoil , the airfoil includes an airfoil section extending in the chordwise direction (X) between a leading edge and a trailing edge , and the outlet port is situated along the at least one surface depression between the valley and the leading edge of the airfoil section with respect to the chordwise direction (X). an external wall extending in a thickness direction (T) between first and second wall surfaces, the first wall surface bounding an internal cavity , the external wall surface establishing an external surface contour and at least one surface depression along the external surface contour , the at least one surface depression having concave geometry established by upstream (174-1, 274-1, 474-1) and downstream (174-2, 274-2, 474-2) arcuate faces sloping inwardly from opposed sides of a rim along the external surface contour to join at a valley , wherein the valley is established at a maximum depth (DM) of the at least one surface depression relative to the rim ; wherein the external wall includes at least one cooling passage extending along a longitudinal axis (LA) between an inlet port and an outlet port , the outlet port is established along the upstream face (174-1, 274-1, 474-1) of the at least one surface depression , and the at least one cooling passage is oriented such that a projection of the longitudinal axis (LA) has a component that extends in a direction (D1) towards the downstream face (174-2, 274-2, 474-2); wherein the at least one surface depression expands outwardly from the valley to establish a diffuser , and the at least one cooling passage interconnects the internal cavity and the diffuser ; and characterized in that the component is an airfoil , the airfoil includes an airfoil section extending in the chordwise direction (X) between a leading edge and a trailing edge , and the outlet port is situated along the at least one surface depression between the valley and the leading edge of the airfoil section with respect to the chordwise direction (X). <EOS>