Prototype will be competing in IMSA/WEC events

Fins have returned. They are just sideways at the moment.

Cadillac partially revealed the Project GTP endurance race car it will be fielding at next year’s 24 hour races in Daytona, Le Mans and Daytona.
The 
prototype racecar has been built according to the new GTP Class specifications. This requires a unique engine and a standard hybrid system which will be used by all other competitors.

The Cadillac crest is on the coupe’s nose, and there are four distinct aerodynamic fin elements that extend inward from the fenders. These fin elements act as a modern homage to the brand’s iconic tailfins from the 1950s.

GTP will be the top-ranked class in the U.S.-based IMSA Racing Series and is being harmonized to the WEC (World Endurance Championships) Hypercar class, so they can compete in races overseen jointly by both sanctioning bodies.
Cadillac race cars won 24 Hours of Daytona four times straight, from 2017 to 
2020 according to the current regulations. However, it hasn’t been back to Le Mans since 2002.
It will face entries from Acura, BMW, Porsche, Acura, and Ferrari when it returns.