It features a classic, relaxed design suitable for both toddlers and young children. Here are the specific details of the style:
Top: A short-sleeved, crewneck t-shirt.
Bottom: Matching full-length jogger-style pants with an elastic waistband and a decorative drawstring.
Pattern: An all-over print
Fabric: It appears to be a soft, breathable cotton jersey or a cotton-spandex blend, which is standard for high-quality children’s sleepwear.
This type of set is often referred to as "unisex loungewear" or a "t-shirt and jogger PJ set."