Yes, Biden is talking about doubling capital gains taxes.

I think it is likely we will see a bifurcation of capital gains tax assessed on equities vs. bonds in the future, with taxes increasing on equities and remaining or getting lowered on bonds. The tax regime will make it more attractive for investors to hold U.S. treasuries on the margin, suppressing bond yields and easing the pressure on the Government to fund itself. I anticipate we might see other forms of capital controls and legislation along with this which encourage or mandate the holding of U.S. treasuries in certain investment products (retirement target-date funds, mutual funds). The government needs someone to buy its debt, and it likely that responsibility will ultimately fall on the shoulder of the U.S. tax payer.