Cara Delevingne is the latest celebrity to lend her naked body to Marc Jacobs for his "Protect the Skin You're In" clothing campaign, which has been raising money for skin cancer research since 2006. We'd all do well to be a little more critical of the "shopping as activism" model, but in this case, all proceeds (typically it's just some) from the sale of the $35 tees are donated to the NYU Cancer Institute at Langone Medical Center. So, two worthy causes: 1) Promote skin cancer awareness and help contribute to finding a cure, 2) boost Cara's international celebrity.
Wanting to wear a designer T-shirt with a naked supermodel on the front of it is probably driven by motives more impure than wanting to help fund a cancer research institute. Still there are worse ways to satisfy your celebrity fandom; the "Protect the Skin You're In" campaign demonstrates a solid commitment to the cause from the brand. Other designers might do a shirt like this as a one-off and only donate partial proceeds to charity. The campaign's Facebook page lists the names of 45 celebrities that have previously participated: These tees have seen everyone from Chloe Sevigny to Naomi Campbell, making the line appeal to a range of cultural types — everyone from hormone-addled bros to dorky fashion girls could find a version of the item they'd like to own.
The shirts are manufactured with 100% cotton. I've reached out to Marc Jacobs for more information about where these T-shirts are made and how they're sourced and will let you know what I find out.