Yet there's one signature campaign pledge — to round up and deport millions of undocumented immigrants — that has many executives across the country on edge. The proposal, if implemented even remotely as vigorously as Trump at times promised, would squeeze a labor pool that companies like Dunkin' Brands Group Inc. and Bojangles Inc. say has already been tightening for months. That in turn stands to further drive up labor costs at a time when many businesses are facing jumps in state-set minimum wages.