I have searched for a keyword "MLM" in Google Trends (location - Benin) which shows me there is some rising searches about this term but when I search this keyword in Google Keyword Planner Tools with the same location (Benin), I didn't get any result. What is the reasons can anyone tell me? Which data is correct Google Trends or Google Keyword Planner Tool for keyword analysis?
Both are correct. Those are different data.
Keyword Planner shows absolute numbers, while Google Trends shows normalized data of user behavior. Normalized means here in general in proportion to time and location
Google keyword planner now shows approximations of search volume for keywords unless you are a paying member of the keyword planner platform in which case the search volume should be more exact.
If keyword planner is showing a search term to have for example, 200-2k searches per month, and the search volume jumps from 300 to 1500, keyword planner will still likely show the search volume as being 200-2k searches per month, whereas Google trends will show the search volume as going up 5x from 300 to 1500.
It's also possible that you didn't get any result in Keyword Planner simply because there is not enough search volume for Google to be reporting on it while Google Trends will still show it.
Also, Google Trends search volume data updates hourly, whereas Keyword Planner may take much longer to update and show search volume changes. As a result, if a keyword goes from 100 monthly searches to 2,000, keyword planner may take a while to react to the search volume change whereas Google trends will display it immediately.