You have four different request status:
1) Accepted: you clicked on the green tick
2) Declined: you clicked on the red cross
3) Cancelled: either the campaign was out of stock so all the pending requests were automatically cancelled, either the influencer cancelled her/his request (before it was managed by your brand)
4) Expired: total number of influencers that expired a credit, meaning that they didn't respect the compulsory deadline to publish the review (after 35 days for Instagram and 42 days for YouTube, counting from the product's shipment date).
You can find the number of Declined, Cancelled and Expired requests on the 'Others' bar.