While the product announcement and review dates are still TBD, the RTX 4070 should be available in April, although without a specific date, as pointed out by Videocardz.com.
There have been plenty of rumors regarding the RTX 4070, and there are three subvariants of the card, including two reference and one Founders Edition card. These will carry the PG141-SKU343, PG141-SKU344, and PG141-SKU345 SKU numbers.
The RTX 4070 is expected to be based on AD104-250/251 GPU and it is basically a cut-down version of the RTX 4070 Ti, packing 5888 CUDA cores and 12GB of GDDR6X memory on a 192-bit memory interface. The TDP is dropped down to 200W, and the GPU is expected to boost up to 2475MHz.
We will probably hear more as we draw closer to the rumored April launch date.