As you may know, a major barrier delaying international distribution of COVID-19 vaccines is intellectual property restrictions. Biden could remove that barrier by supporting a TRIPS Waiver.
Such a move is supported by many organizations such as Oxfam, Medicins san Frontieres, and Human Rights Watch. Without it, the pandemic will continue, quite likely increasing, and new lethal variants are certain to arise.
A TRIPS waiver is important to save perhaps millions of lives worldwide, but also for bringing the pandemic under control in the US.