A majority of Americans don't know that their taxes are about to increase.
According to Cato Institute's
The TCJA was passed by a 51-49 Senate vote on Dec. 2, 2017, and signed into law by President Donald Trump during his first term on Jan. 1, 2018. The overhaul to the Tax Code decreased the tax rate for five of the seven individual income tax brackets, raised the standard deduction, suspended the personal exemption, removed a mandate requiring individuals to purchase health insurance under a provision of the Affordable Care Act, and raised the Child Tax Credit and created a nonrefundable credit for non-child dependents, among other things.

Part of the lack of awareness surrounding the expiring tax cuts is simply due to unfamiliarity with the TCJA: Only 9% of people are very familiar with the act, 28% say they know a moderate amount about it, and 34% say they know nothing.
When respondents learned that the TCJA provisions will expire, 53% said that Congress should either make the cuts permanent (36%) or extend them temporarily (17%). Only 13% said they wanted Congress to let the tax cuts expire, and 34% didn't know enough to say.
Respondents' support for extending the tax cuts increased when they learned that the average person's taxes will increase between $1,000 and $2,000 a year — 57% said to make the tax cuts permanent, and 28% said to extend them temporarily.
Eight in 10 respondents say they worry they cannot afford to pay higher taxes next year. But only 45% expect their personal tax bill to increase, while 5% expect it to decrease and 23% think it will stay the same. Twenty-six percent don't know what will happen.
Respondents were split on whether they thought the U.S. can afford the tax cuts: 45% said the U.S. can afford to make the TCJA permanent, 21% said the country cannot afford to do so and 34% said they don't know.
However, 51% felt their taxes were handled fairly, while roughly half of respondents think their taxes are too high (55%) and believe their tax bill exceeds their fair share (55%).
The Cato Institute is a libertarian public policy think tank based in Washington, D.C. It surveyed 2,000 Americans from March 20 -26 for the report, in collaboration with YouGov.