What you're looking at is a cryotherapy chamber that LeBron James uses to trick his body into thinking it's freezing. The chambers gets to around minus-300 degrees and James and other athletes will typically stay in a machine like this for two or three minutes. It apparently helps his body recover from overexertion.
Professional teams use things like this all the time -- anything to gain an edge, really. The Anaheim Angels do, too. As do the Phoenix Suns:
Suns have a cryotherapy chamber, instead of individual tube focusing on body parts, it's a capsule that covers whole body from neck down— Amin Elhassan (@AminESPN) May 6, 2015
The image simply makes LeBron look more superhuman than ever.