Assuming all US DOE goals are achieved, FCHEVs long-haul trucks will be economically competitive by 2030, against diesel and H2ICE vehicles. However, progress on freight decarbonization technology solutions remains highly uncertain. Energy cost (diesel, electricity, H2), component durability, thermal management, critical material bottlenecks, performance degradation, fueling/charging infrastructure, CAPEX all contribute to this uncertainty. Total Cost of Ownership (TCO) analyses (Argonne National Laboratories and e-mobil BW) show that fuel-cost is critical to the competitiveness of any H2-fueled vehicle (both FCHEV as well as H2ICE solutions); however, H2ICE could de-risk some of the investments, jump-starting the H2 economy.  H2ICEs may also remain the preferred long-term technology for several high power, lower VMT applications. Achieving high drive-cycle efficiency and powertrain density while fulfilling emissions legislation remains a key R&D priority for H2ICEs.