Codenamed the OEMQN Product Name EV1, the Core i5-1035G1 is likely an entry-level version of the Surface Book 3. Sporting a 256 GB SSD and 8 GB of RAM this time, the long-awaited Surface Book 2 successor is expected to launch sometime this Spring.
https://www.notebookcheck.net/Possible-Surface-Book-3-powered-by-an-Intel-Core-i5-1035G1-and-8-GB-of-RAM-appears-on-3DMark.459841.0.html