True Seeing is a divination spell that states:
For the duration, the creature has truesight [...]
While Mind Blank states:
Until the spell ends, one willing creature you touch is immune to psychic damage, any effect that would sense its emotions or read its thoughts, divination spells, and the charmed condition. The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.
Let's say that the Rogue had Invisibility and Mind Blank cast on him, and the Wizard cast True Seeing on himself. How do these spells interact?
The discussion at my table hinges on the fact that True Seeing doesn't target or affect the Mind Blanked rogue, so his immunity is not relevant. The Wizard would simply gain Truesight and would spot him. Is this correct?