If a traveller joins for example Asr prayer in congregation and he was able to pray two rakat with the congregation. Does he do salam with the congregation because he is a traveller or does he stand after salam and pray two rakat?

Ustadh AbdulAziz al-Haqqan

He stands after their tasleem and completes four, he does not give salam with them, because whoever prays behind a resident imam completes the prayer, otherwise his salah is not valid.