Pharisees (and the Sadducees) were Jewish religious parties in Jesus’ day.
The Sadducees denounced John the Baptist (Matt 3:7-8). They both opposed Jesus and His teachings (Matt 16:6,11,12, 21:12-13; Mark 11:15-18; Luke 19:47) and the apostolic Church (Acts 5:17, 33).
One of the main differences between the Pharisees and the Sadducees was that the Pharisees believed in the resurrection (Acts 23:6) but the Sadducees did not (Matt 22:23). They accepted only the written Law of Moses as authoritative and rejected the subsequent revelation.
As a result, the Sadducees denied many of the doctrines held by the Pharisees and by Jesus, including the existence of angels and spirits (Acts 23:7-8).