A $700 blood test promises to detect 50 different kinds of cancer. The results come with major caveats.

Grail's Galleri test uses two vials of blood to screen for over 50 different kinds of cancer.

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• Grail's Galleri test promises to detect cancer signals in your blood.
• It's good at finding advanced cancers, but can miss early-stage cases.
• Telehealth company Hims & Hers is offering Galleri at a $250 discount, but there's a catch.

A Super Bowl ad airing this weekend by telehealth company Hims & Hers pokes fun at "rich people" and their obsession with living longer.