Apple will include a new file system — the "Apple File System" (APFS) — with the debut of macOS Sierra. The developer documentation describes it as a “new, modern file system for iOS, OS X, tvOS and watchOS.”
AFPS is optimized for Flash/SSD storage and features “strong encryption, copy-on-write metadata, space sharing, cloning for files and directories, snapshots, fast directory sizing, atomic safe-save primitives, and improved file system fundamentals.”
APFS is released as a Developer Preview in macOS Sierra, and is scheduled to ship in 2017, according to Apple. It supports nearly all of the features of HFS+, and offers improvements over HFS+, including 64-bit inode numbers, 1 nanosecond timestamp granularity, an expansive block allocator, support for sparse files, and a crash protection scheme.
The core of HFS+ was build 30 years ago. HFS+ is a proprietary file system developed by Apple that has served as the primary file system of OS X. HFS+ was developed to replace the Hierarchical File System as the primary file system used in Macs.
APFS also provides several new features, including optimization for Flash/SSD storage, copy-on-write metadata, space sharing, cloning of files and directories, snapshots, fast directory sizing, and atomic safe-save primitives. You can create an Apple File System container on an external hard drive, partition, or disk image on OS X 10.12 using the diskutil command.