This is the cover of an Arknights concept book Hoshieve sold at C95, December 2018, before Arknights launched (May 1st, 2019 in China). Apparently it has become quite the popular collector item with Arknights' popularity, with copies selling for 4000 yuan, 50'000 yen, $800... and as with most comiket books it's basically impossible to get ahold of currently. One trillion danboorucoin to anyone who can find scans of this.

Someone on Biliblili posted a video looking through it. There's also another book but I found even less about that.

Ah yes, the legendary concept book which, among its art, contains an earlier rendition of Amiya where she's giving off M16A1 vibes. May scans of this book reach us some day.