Trump's proposed budget for FY26 does include slashing the national cancer institute by 37%, which is huge. But that hasn't passed yet.
In contrast the "big beautiful bill" that did pass didn't cut cancer funding. (It did include the Orphan Cures Act, which cuts regulation and eases reimbursement for some diseases including cancer, but doesn't directly increase funding for them).
So, it's premature to declare drastic cancer cuts as a done deal, although it's a big threat, although it's not "zeroing out" federal funding.
Also how much of cancer research is funding by the federal govt vs private industry I'm not sure - but private research certainly won't be discontinued, since it's profitable. One of the cancer medicines I'm on is $23,000 per little IV baggie. Not sure how much of that goes straight into dividends and buybacks vs research.