I don't listen to NPR, but when I watch PBS Newshour they announce all their sponsors at the beginning of every program and mention the fact of their sponsorship again when there's any connection to an individual report. A recent example that springs to mind if the train derailment and subsequent pollution problems in East Palestine, Ohio; the rail firm BNSF sponsors the newshour but this didn't seem to have any impact on the volume or tone of coverage.