Refers to something newly found or devised, often with a sense of breakthrough or innovation.
The new discovery shocked the scientific community.
His newly invented technology was patented.
新発見 (a new discovery) looks similar in kanji to 新発売 but refers to finding something new, not releasing a product for sale.
Compound of 新 (new) and 発見 (discovery). The reading しんはっけん follows standard on'yomi with rendaku on the second element.