The Keystone XL pipeline was first proposed in 2008 under President George W. Bush. The proposal included oil facilities and an 875-mile pipeline starting in Alberta, Canada that would carry up to 830,000 barrels of crude oil per day to Nebraska, where the pipeline would join an existing pipeline and carry oil to Gulf Coast terminals.

President Obama repeatedly denied applications for the Keystone XL and vetoed the 2015 Keystone XL Pipeline Approval Act. President Trump invited resubmission of the application on Jan. 24, 2017 and issued a presidential permit for the project on Mar. 29, 2019. TransCanada announced construction would move forward on Mar. 31, 2020. However, a court ruling revoked a crucial permit on Apr. 15, 2020, further delaying the project.

Sources:
Matthew Daly, "Trump Issues New Permit for Stalled Keystone XL Pipeline," apnews.com, Mar. 29, 2019
Nina Lakhani, "Major Blow to Keystone XL Pipeline as Judge Revokes Key Permit," theguardian.com, Apr. 15, 2020
Olivia Rosane, "Keystone XL Pipeline Construction to Forge ahead during Coronavirus Pandemic," ecowatch.com, Apr. 1, 2020