What could cause inflation to return today?

The current absence of inflation in OECD countries has considerable implications: interest rates remain very low , very high debt ratios can be maintained , there is no mechanism that could trigger a recession. This begs the question : what could cause inflation to return? A change in the functioning of labour markets, with wage earners regaining bargaining power. But if one country alone made such a change, it would face problems with rising labour costs in a world of strong competition between countries (this would be the case in particular for the euro-zone countries, which would not be able to devalue); A rise in energy prices due to the energy transition: purely renewable energy will be much more expensive than the energy available today; Protectionism, if it put a halt to OECD countries’ imports of cheap products from emerging countries.