With Perserverence currently on mars looking for microbial life and creating samples for the Mars Sample Return mission that is currently expected to arrive on earth in 2033, will we detect evidence of life on Mars before 2040?

Will resolve YES if a 5 sigma discovery of martian life is announced before December 31st 2040.

https://mars.nasa.gov/mars2020/

https://mars.nasa.gov/msr/#Facts

Mars Sample Return - NASA

NASA and ESA are working to plan ways to bring the first samples of Mars rocks and soil back to Earth for detailed study.