This clinical trial will test the safety and efficacy of a treatment regimen of the remdesivir plus the anti-inflammatory drug baricitinib for COVID-19. It is the next iteration of NIAID’s Adaptive COVID-19 Treatment Trial (ACTT), which began on February 21, 2020 and evaluated Remdesivir. In this next trial called ACTT 2, all participants will receive remdesivir or remdesivir with baricitinib.