According to literature tendon of biceps brachii does express PECAM1. According to Uniprot.org, PECAM1 is expressed in tendon of biceps brachii, lung, brain, platelet, liver, leukemic t-cell, among other tissues. Regarding which tissues have PECAM1 expression, here are a few articles citing expression in various tissues:
Brain, Pubmed ID: 15489334
Leukemic T-cell, Pubmed ID: 19349973, 19690332
Liver, Pubmed ID: 19159218, 24275569
Lung, Pubmed ID: 14702039
Platelet, Pubmed ID: 18088087