If you're trying to say that immunostimulant is a term of art distinct from immune checkpoint inhibitor, then fair point.
But what it seems like you're saying is checkpoint inhibitors don't "enrage/activate" the immune system, and they only target tumours, and both points are misleading if not outright wrong.
Yes, it's a different term and entirely separate category of drugs.
Checkpoint inhibitors cut the brakes. This reduces their ability to detect "self," and attack blindly.
What they don't do is poke immune cells with a stick to anger them like chemoattractants and cytokines. This approach can be used to signal, "hey, the tumor is over here." Causing them to attack more intelligently.
If you would like to learn more, I would recommend the books: (a) molecular biology of cancer; mechanisms, targets, and therapeutics, and (b) handbook of therapeutic biomarkers in cancer.
But what it seems like you're saying is checkpoint inhibitors don't "enrage/activate" the immune system, and they only target tumours, and both points are misleading if not outright wrong.