The phrase "caved in to" implies giving in to pressure or changing one's stance on something. Synonyms for this phrase might include acquiesce, relent, yield, capitulate, or succumb. Each of these words suggests a similar idea of giving up on a position or decision, but they may have different shades of meaning or connotations. For example, "acquiesce" implies a reluctant or passive acceptance, while "yield" may suggest a more deliberate choice to step back from a conflict. And "succumb" suggests that the pressure or challenge was too great to resist, while "capitulate" implies a formal surrender or acceptance of superior force.