The Mars 2020 mission will use advanced technology to seek signs of microbial life, but has it already been discovered …

http://www.futuresciencenews.com/2017-08-29-science-con-nasa-claims-it-will-seek-life-on-mars-in-2020-mission-but-it-already-covered-up-proof-of-life-from-the-1976-viking-mission.html