Heya,
If I had to guess:
Looking at the catchlights, it could be natural light, the sky reflecting in the eyes is broad and takes up the whole eye, no small catchlights indicating a little lighting setup. The little thing in the middle looks to be the photographer or mom to get the baby's attention. If natural light, they're simply in the shade, exposing up, which is why the background foliage in direct sunlight is overexposed. And to hide the overexposure, it looks like a flare was added in post since it's so spherical and not in line with the natural light. Then use D/B on the baby to bring up the skin and shadows. I don't think lighting was used here.
If I were to do it, and I do a lot of baby shoots, I'd use a big 47~48" modifier with a light and drop ambient more, and expose up with the light.
Very best,