Cap vs Thanos Theory
Quick theory as to how Cap is able to hold off Thanos:
Cap and the team save Vision and the Mind Stone from the Black Order, but Vision is badly hurt in the process.
Cap and the team go to Wakanda, knowing it is the safest place to keep the Infinity Stone.
Thanos and his forces arrive to take the stone.
Vision is too weak to fight and so gives Cap the Mind Stone to give them a fighting chance, possibly sacrificing his life in the process.
Cap wields the Mind Stone into battle (possibly in his new shield) which is why he can do battle with Thanos.











