This is a fairly antiquated term meaning “future endeavors,” and is usually found in statements like “Excel Fertility welcomes not only your current staff but also those who will join us as future endeavours” or “But for the sake of time, I’ll discuss these three subjects next round. Future endeavours.”
Very rarely used in modern speech or writing. You are more likely to find the phrase used if someone is referencing writing from an earlier period of American English use–around 1852-1974–or if someone says something such as, “I sinned yesterday–but that’s a story for another day! It’s time to get on with this one!”