Pantheon is one of the only perfectly symmetrical maps. A/C are located just next to spawn and are easy to capture during Control, but the hotspots on the map are the courtyard and hallway. Going through either passageway leads to the Special Ammo crate for the respective side and you can see straight through the courtyard, a perfect area for snipers. The same thing applies to the hallway, the middle has the Special Ammo crate but it’s a long straight hallway where snipers choose to take out their frustrations on easy targets. Unless you’re sniping, you don’t want to be sitting on the far ends of these areas.
B is hard to contest, it’s very open and there are lots of angles in. Sometimes the best attacking angles aren’t from the passageway, but from the hallway and bridge where you can flank. The Heavy Ammo spawns at hallway and bridge respectively, usually a hotly contested venue with the amount of open space to these areas as well. Use the waterfall on the hallway Heavy Ammo to surprise Guardians that would camp this spot waiting for the Heavy Ammo to spawn, pre-grenading the area is also useful for whittling down your opponent before charging in blind.
Key spots to hold down are the oppositions passageway if you prefer short range weapons, and Hallway/Bridge if you prefer to snipe. Taking the Hallway/Bridge is better than sniping just the Courtyard because you can angle in on opposing snipers this way and clean up Guardians who hide near the middle pillar. It’s a very fun and balanced map, just be wary of the numerous angles and how to best avoid getting stuck with your back to the enemy.