Hyder Ali, who rose to become the de facto ruler of Mysore, received Bengaluru as a jagir in 1759. He rebuilt Kempegowda's mud fort in stone and started a garden in 1760 that became Lalbagh.
His son Tipu Sultan extended Lalbagh, bringing in plants from across the world, and completed the teak-built Summer Palace near the fort in 1791. Both still stand. See Tipu Sultan's Summer Palace and Lalbagh.
Further reading: Tipu Sultan's Summer Palace on Wikipedia.