To expand, cancelling the Keystone XL pipeline primarily fucks over two groups: Canada, and the workers who were going to build it.
The agreements and contracts for Canada to sell heavy oil (Canada's #1 export) to the United States are already in place, and the unit price of the oil is already set. With the pipeline cancelled, the same amount of oil is going to be sold to the United States by Canada for the same price, but it will instead need to be shipped by rail and by truck, which are way more expensive methods of transport vs using the pipeline, which means Canada is completely getting fucked over on the deal, and reducing the profits from the agreement by a massive amount.
Not to mention that Canada has already invested $1.5B in building the pipeline so far, and there's no clause in the agreement for any form of reimbursement.
So in essence, cancelling the pipeline does nothing to reduce the amount of oil being brought into/used in the United States, doesn't cost the United States anything, and just totally fucks over Canada and the blue collar workers who would have built the pipeline. So, I guess Biden is based after all?!?