Sierra Ops: Season Pass

Sierra Ops : Season Pass includes the following DLCs:
1. Sierra Ops : Episode 2 - Dissonance and Resonance
2. Sierra Ops : Episode 3 - Unending Dusk
3. Sierra Ops : Episode 4 - Cadence of the Morning Star

All the remaining 3 episodes will cost 9.99 USD each, and by buying the Season Pass, you save 40% off (or more during Steam sale) compared to buying the episodes individually!

Episodes 2, 3 and 4 are still work in progress as of March 2, 2020.

Source:

Steam Store Description