iframe cookie blocked samesite policy

Since version 84 of chrome, linkedin content iframes are totally blocked and chrome displays the following message :

A cookie associated with a cross-site resource at http://google.com/ was set without the SameSite attribute. It has been blocked, as Chrome now only delivers cookies with cross-site requests if they are set with SameSite=None and Secure.

I did a lot of research but I still can't find how I can set up my Content-Security-Policy and my headers exactly so that they accept iframes feeds from linkedin on CI 3.14.

I tried an ini_set in the config.php : 

Code:

ini_set('session.cookie_samesite', 'None');
ini_set('session.cookie_secure', TRUE);

I tried to modify the headers : 

Code:

$this->output->set_header("Content-Security-Policy", "default-src 'self' *.linkedin.com");

But nothing work at all ... How i can modify my headers, for accept the linkedin feeds iframe as 1-2 weeks ago ?

Thanks a lot by advance