A direct Chinese involvement during an Indo-Pak conflict seems highly unlikely in any scenario. India's own ties with China have high economic stakes involved and both are keen to keep the borders calm. However, China has more than compensated for this cold peace with India by developing a strong strategic relationship with Pakistan at the expense on India's security concerns.
Irrespective of a conflict, the underlying factor driving the Sino-Pak strategic cooperation is the need to undercut Indian preparedness. On the naval front, Pakistan is set to receive Chinese warships and submarines. The Pakistan Air Force operates Chinese JF-17 and Chengdu F-7 Fighter jets. Pakistan's nuclear program would have been incomplete without Chinese assistance, as it supplied weapons grade uranium and centrifuges to Pakistan.
There are reports, confirming, the presence of Chinese soldiers in Pakistan occupied Kashmir. Indian strategic circles have taken into consideration the possibility of a two front war as the Ladakh region is sandwiched, between, Pakistan occupied Gilgit Baltistan to its west and Xinjiang to its east. Bilateral strategic ties are so deeply entrenched that there would will always remain a shadow of China in an India-Pakistan conflict.
Even with respect to the regional security situation, China has thrown its support behind Pakistan in supporting the Taliban and even hosting its leaders for discussions, despite being aware of Taliban's attacks on India's diplomatic assets and overall interests in Afghanistan. Similarly China has twice in the past blocked UN sanctions against leader and founder of Jaish e Mohamma,d Masood Azhar, and while USA, UK and France once again move to introduce a ban on the known terrorist, there is as yet no clarity about China’s position.