I've noticed that every dlc yet has come out on an tuesday and the march dlc will come the 13 march wich is also an tuesday and if I remember correct the game itself realesed on an tuesday AANNNNDDD the dlc "collection" will also be realesed on a tuesday, and the campaign mission is called "black tuesday" (I think IW likes tuesdays). it's been about 4 week between them so from this you can probobly figure out when the dlc will be realesed.

Here under I've made a list when the dlc have come out and when they probobly come out. And there are 22 drops and 5-6 in each collection means 4 collections and I've put double date when 5-6 drops has came out, which leads to these dates (can't be 100% right but it must be close)

January:       24

February:      21

march:       13/20

april:            24

may:          15/22

june:            19

july:           17/24

august:        21

september: 11/18