On Assignment

On Assignment” May 22

Sunday, May 22, "On Assignment"...

You can watch the full May 22 'On Assignment' report here.

The Face of Terror

In an exclusive and unprecedented interview with Richard Engel, a New York City man who left the United States to join ISIS and then fled the group after five months is speaking out and revealing the disturbing details of his journey into the heartland of terror — and warning others not to follow in his footsteps.

American ISIS Informant: 'I Lost Sight of How People Could Be So Evil' 3:32

The Clone Zone

Harry Smith with Laura Jacques and Richard Remde as they greet their two boxer puppies cloned from Laura's beloved dog Dylan. NBC News

Harry Smith and the 'On Assignment' team headed to South Korea, to the only lab that commercially clones dogs. The SOOAM Biotech Research Foundation in Seoul has already cloned 780 dogs for clients across the world. The price tag for a genetic duplicate of a puppy? Roughly $100,000.

The Clone Zone: Not just any birth 0:45

Hacking Cancer

Keith Morrison and Sean Parker NBC News

After losing a close friend to cancer, Silicon Valley billionaire Sean Parker decided he needed to do something to help in the fight against the disease. So earlier this year, Parker launched the Parker Institute for Cancer Immunotherapy, focused on the emerging field of cancer immunotherapy.

Hacking Cancer: His name is Sean Parker 1:13