There's naming something cryptically and then there's naming something Phelps Vs. Shark: Great Gold Vs Great White, which is so blunt it circles past obvious-town and settles right back into vague-ville.

Discovery is naming a Shark Week program this, although it's worth looking just to make sure that that title isn't for a SyFy feature (with a sequel called Phelpsnado: The Gilding).

Apparently Shark Week wasn't enough of a meme for the Discovery Channel, so they decided to make humans race huge fish because ... reasons.
Discovery billed the event about as dramatically as one would expect, stating in a press release:

They are one of the fastest and most efficient predators on the planet: Sharks. He is our greatest champion to ever get in the water: Michael Phelps. 39 world records. 23 Olympic golds. But he has one competition left to win. An event so monumental no one has ever attempted it before. The world's most decorated athlete takes on the ocean's most efficient predator: Phelps V Shark – the race is on! Produced by Peacock Productions.

The language here is interesting. For starters, Phelps has a lot of competitions left to win. He isn't a national discus champion yet and his chess game needs a lot of work. Also, some people have probably attempted to outrace a shark. Under different circumstances, but they probably tried. Some may have even won. Also, Discovery seems to be equating a "champion" with a "predator," which likely only applies to Kobe Bryant.

The capacity in which Phelps will be racing this shark is unknown, but Phelps did share an Instagram post of him cage-diving with a shark, which he called one for the bucket list. Unfortunately, Discovery is going to keep us in the dark until July 23, but until then it's probably safe to assume that this race was pretty "off-the-books."