Pokémon pass the 5th degree RAID chief, Giratina, is currently out of the game and has been replaced by the famous monthly Pokémon, Cresselia.

Here's the official info straight from the Pokemon GO website:

"Coaches, because the famous year of pokemon is coming to an end, will be a fascinating occurrence of the famous pokemon, first found in the area of Sinno.

"Psychic-type famous pokemon Cresselia will join the raids on November 20 at 1: 00 PM PST! Details below."

"Do not miss the chance to catch this famous pokemon, before he returns to his own Shrine! Stay safe and successful studying!"

For those who need this explanation, it means actually what Cresselia now available as a RAID boss.

Cresselia remains in as a RAID chief until 18 December 2018, in 13:0 0 PST (GMT -8).

This is a report, expect more detailed information, in that the number of the best counters and almost everything else. 

Information about the key database Pokemon GO:
GO Pokemon Cresselia-legendary pokemon with a psychological limit CP 2857, 152 attack, defense, endurance 258 and 260 in Pokemon GO.

Initially, he was found in the area of Sinnoh (gen 4). Cresselia is vulnerable to misses, black and illusory move image.

Cresselia's best moveset Psycho cut clairvoyant and psychic Futuresight, with a cycle of (weaving) DPS damage of 14.47 per second.