Peacock does offer certain content in 4K Ultra HD to Premium and Premium Plus subscribers on some supported devices that are 4K Ultra HD compatible.
How do I tell if my device is 4K Ultra HD compatible?
You will need to check with your device’s manufacturer for your specific model number to confirm 4K capabilities. Only some compatible devices can play 4K Ultra HD content on Peacock at this time.
How do I tell if content is available in 4K Ultra HD?
Content that is available will have a 4K UHD badge in the Information section of the content.
How do I turn on/off 4K Ultra HD?
Content that is available will automatically play in 4K Ultra HD on compatible devices with a Premium or Premium Plus subscription and cannot be turned off.