In the United States, qualified immunity is a legal principle of federal law that grants government officials performing discretionary (optional) functions immunity from lawsuits for damages unless the plaintiff shows that the official violated "clearly established statutory or constitutional rights of which a reasonable person would have known".

Under 42 USC § 1983, a plaintiff can sue for damages when state officials violate their constitutional rights or other federal rights.

https://en.wikipedia.org/wiki/Qualified_immunity

Qualified Immunity only sets the bar or threshold that you have to meet in order to sue.