Its two-piece matching set, specifically a shirt and shorts set.
This outfit consists of:
A collared, short-sleeved button-down shirt:
The shirt has a classic collar, short sleeves, and a button-down front, featuring a pattern with "CHRISTIAN DIOR" lettering.
Matching shorts:
The shorts are designed to complement the shirt, sharing the same pattern and color scheme, and appear to have "CHRISTIAN DIOR" branding.