Ashes of the Singularity: Escalation was released last November for Windows as a real-time strategy game out of Oxide Games and Stardock. Ashes of Singularity was notably the first game released with DirectX 12 support. The developers are moving ahead with their Vulkan API support.
The developers noted in their monthly update, "The Vulkan work is largely completed. However, it won't be until June before it's released as there is a ton of compatibility and optimization work to be done given the game's popularity as a benchmarking tool for high end graphics."
While it's a good sign for Linux support with now having Vulkan as an alternative to D3D12, it's not yet on the radar. The post went on to say, "Now, Vulkan doesn't mean Linux. It just means that the door is open to Linux. The challenge with Linux is that the user base has to be sufficient to justify it. Right now, the biggest challenge for Ashes remains the hardware requirements. Most PC gamers cannot run the game. This was always known which is why we have always viewed the game as a very long-term endeavor (hence the roadmap we've posted)."
Priorities ahead of a Linux port are improved compatibility/stability, support the modding community, adding more units into the game, adding more depth to the gameplay, and improving performance / lowering system requirements. "That doesn't mean no Linux version, it means it's not yet on the radar."
More details in this forum post.