Relationship Between Increasing Opportunity Costs and Increasing Returns

What is the relationship between increasing opportunity costs and “increasing returns”? I know that the former is when the cost of doing something increases the more you do it. In this case, it makes sense that as we produce more of one good, we have to give up more and more of the other good due to resources not being suitable. Now, how does this relate to increasing returns which I understand to be the increase in costs when production rises?