Hi @bhamrick,
Happy to help!

To exclude a person from a campaign if he is already in any of your sequences you can use the Klaviyo exclusion filters.
There are several options for setting them up

- Go to the "Lists and Segments" tab in your Klaviyo account and create a new segment.
- Add conditions for the people you want to include in your campaign. For example, you can include people who have agreed to a certain offer.
- Add an exception filter for people who are currently in any of your sequences. 
Preview the segment to make sure that the people you want to exclude are not included in the segment.
Use this segment as your recipient list when you send the campaign.
With this approach, anyone who is currently in one of your sequences will be excluded from the campaign, even if they meet the other conditions you set.

It's worth noting that if someone is in more than one promotion sequence, they will be excluded from the campaign if they are in any of them. If you only want to exclude people if they are in certain flow, you can use the " Flow" condition in the "Flow Filters" section of the Segment Builder to target specific flow.

P:S If you have any question just let me know

@Irrra thanks. I don’t see how to make an exception rule for people currently in a flow. I can exclude people who initially opted in to a list that started the flow, but that wouldn’t include anyone who had completed the flow. Where would I do this?

@bhamrick 
You can use splits in this case

@Irrra I’m not understanding, what’s a split? If you can provide an example that would help.

You could try consolidating into a single flow using splits, not use if that is what @Irrra meant. 

The flow would trigger when someone is added to your newsletter list. You can set up splits based on which form a user signed up for or their source. We do this a lot when we test welcome offers. 

For example, we might run a 15% off popup and a 20% off popup. In the flows we will do a split based on which version of the signup form the customer used. This way they get the correct discount level in their email and we can measure the effectiveness of the the different welcome offers from signup conversion rates to the conversion rates of the emails/sms messages.

To exclude individuals from receiving campaigns if they are already enrolled in any of your nurture sequences, you can use tags or custom fields in your email marketing platform. Whenever a person enters a nurture sequence, you can assign a specific tag or update a custom field associated with that sequence to their profile. When you are ready to send a campaign, create a segment or filter based on the presence of any of those nurture sequence tags or the value of the custom field. 
Thanks and Regards