Cheek implants or fat graft first?

Fat should be placed first as you don't want to potentially infect the implant. Moreover, the fat should be placed on periosteum, which would not be possible with an implant sitting there.

For unique cases where a variety of modalities could be used to treat the condition, I would suggest an in-person or virtual consultation to develop a custom and effective treatment plan. It is difficult to precisely define the best option without collecting the same information. I suggest reaching out to an expert for a consultation with surgical and non-surgical methods to get a comprehensive option. Best, Dr. Emer.

I suggest having the procedure that you think is going to have the greatest impact first and then get a reassessment and see if you need secondary procedures.
You didn’t include pictures or any statements in what part of your face you’re going to have fat transfer. I don’t think there’s any yes or no answer to your question.
Focus your efforts on finding the best providers and follow their recommendations.
Best,
Mats Hagstrom, MD