Apple has improved the iPhone 12’s camera hardware only a little over the iPhone 11 Pro.
(Both are triple-camera affairs, with what seems to be the same three 12-megapixel sensors covering wide, ultrawide, and 2X telephoto angles. The most obvious addition to the iPhone 12 Pro here is a LiDAR scanner, which makes it easier for the iPhone to figure out depth information.)
the 12 Pro screen is bigger, 5G connectivity, MagSafe, A14 CPU.
The iPhone 12 Pro is clearly a better phone than the iPhone 11 Pro but you’ll only really see clear evidence of this a year or two down the line.