For some patients with bone metastasis of squamous lung cancer, immunotherapy will be effective, taking the most common pembrolizumab as an example. A study enrolled 559 patients with primary metastatic squamous lung cancer, who were randomized 1:1 to receive pembrolizumab in combination with chemotherapy (Group A), versus chemotherapy alone (Group B). The results showed that pembrolizumab combination chemotherapy significantly prolonged the median PFS (progression-free survival time), which was 6.4 months in group A and 4.8 months in group B, and there was no significant increase in adverse effects. In addition subgroup analysis suggested that different PD-L1 expression subgroups benefited from combination chemotherapy treatment. Based on the results, the NMPA has approved pembrolizumab in combination with carboplatin and paclitaxel (or albumin-bound paclitaxel) for first-line treatment of metastatic squamous lung cancer in 2019.