What's wrong with my new dogwood tree?
Both photos show leaf discoloration from cold damage. We have been swamped with questions about plants of all species showing cold damage after late freezes this spring. It will outgrow that.
The second photo also seems to show the beginning of powdery mildew at the base of the newest leaves (8 o'clock on the photo). It looks like a light film . This is more of a problem as this is a fungal disease that can weaken the tree and make it look unsightly every year.
Read carefully through this webpage: https://extension.umd.edu/hgic/topics/powdery-mildew-trees-and-shrubs
You may want to return it and replace with a powdery mildew resistant variety.