What if there was a molecule that could keep you f

What if there was a molecule that could keep you from getting HIV or, if you already had HIV, could reduce it to undetectable levels in your blood; and if you had cancer, it could keep the tumour from metastasizing, and it could reconfigure the immune response to inhibit tumour growth? What if it could use the same mechanisms to resolve ARDS, GvHD, and other immune disorders? And required only one injection, under the skin like an insulin shot each week, and there were no side effects, no toxicity, no drug interference, and no resistance?

What if such a drug existed?

What would that be worth?