EXO's Chen is enlisting later today.
SM Entertainment will not be revealing his location and time of enlistment, as the idol wants to enlist quietly. He will be receiving his basic training and serve as an active-duty soldier. He's the 4th EXO member to enlist after Xiumin, D.O, and Suho. Xiumin and D.O enlisted last year in May and July, respectively, and Suho enlisted earlier this year in May.
You can read his letter to his fans here. Come back soon, Chen!