The phrase "tremendous boon" means a very helpful or advantageous thing. It refers to something that is extremely beneficial or advantageous for someone or something. Full definition
This was a tremendous boon to the economy, likely sparing many Canadians pink slips they might otherwise have received. (canadianbusiness.com)
With a proper retraining of the workforce, Bignall believes that robots can become a tremendous boon for American society. (businessinsider.com)
There was, however, a very interesting statement within a recent Moody's report that clarified how the new health law has not been a tremendous boon for these hospitals. (beckershospitalreview.com)