nivolumab based treatment
nivolumab alone
mGC or mGEJC - 2nd Line (L2)
mGC or mGEJC - L2 - all population 4   
mGC or mGEJC - L2 - PDL1 positive 1
Comparator:  vs placebo; 
Risk of bias:  low;   some concerns;   high;  NA;