Ok; you live in tax friendly New Hampshire, but commute to work in Boston, which is in a very tax unfriendly state. Massachusetts generally taxes all income derived from within their state. In fairness, they are not alone here. It's a fairly common practice. But along comes Covid 19 and suddenly your employer orders you and around 90% of the other employees to work from home, in your case that being New Hampshire. So who do you owe taxes to? Massachusetts says you still owe them the money because that's where your employer is based. New Hampshire begs to differ.
Enter at least eleven states and the United States Supreme Court.