Is there any promotion on Apple Card?

No.

Apple Card has a permanent 3% cash back when used in Apple Stores, or other select merchants. 2% cash back on all other merchants when using iPhone or Apple Watch to pay through Apple Pay.

Good news! There is currently a promotion for $75 when you invite a friend. When they apply for Apple Card and are approved they’ll receive the $75 bonus when they make their first purchase within 30 days.

You can find the link in your Apple Card in your Wallet app on your iPhone. Apple Wallet > More button > Daily Cash > link to invite friends (see photo).