We have a much more pressing issue than either: lack of working antibiotics... Cancer unsolved does not cause too many issues (it is a terrible disease nonetheless), while solving third world medical problems is mostly matter of goodwill and logistics (and comparatively cheap).
But if we hit a new resistant superbug... That will decimate everywhere, everyone. Think plague combined with malaria. Talking about multidrug resistant strains of bacteria. If just one becomes reasonably virulent we are really out of luck.
We need something new to have in reserve.
Basic research as done in cancer research may or may not help.
AFAIR this is a bit of a dramatization. The primary threat of superbugs isn't a new super plague (which is unlikely). The danger is that a big part of our medicine will suddenly revert to preindustrial mortality rates - surgeries that are routine today will become life-threatening, including probably anything you do at the dentist's. Imagine getting a cut in the kitchen, going to hospital for stitches, and ending up in a body bag. This alone will be both seriously deadly and disruptive to the economy. It is a serious issue indeed.
The basis for my post is the implication that funding cancer research is a "waste", which I disagree with.
The actual major problem would be hospital acquired infections not directly related to surgery. We have some really good asepsis nowadays but it cannot be maintained too long, is expensive and hard to scale.
There's been no effective advance in therapy since then.
There hadn't been any since the late 1950s.
Some conditions are simply resistant to improved theerapies.
(CRISPR or similar direct genetic editing might break the logjam. But it's been a long time. And my friend remains very dead.)
Rather than high-tech aadvances, increased and consistently available medical care and public health measures would be vastly more effective. And always have been.