"Captain America" film series scribes Christopher Markus and Stephen McFeely aren't resting on their laurels for this Summer's 'Civil War,' instead they're hard at work on the freshly retitled "Avengers: Infinity War" film which heads into production towards year's end. Despite the once two-part film being restructured as separate films, Markus and McFeely tell Yahoo Movies they're working on both scripts in tandem.